Devices, systems, and methods for performing optical and electrochemical assays

ABSTRACT

This present invention relates generally to devices, systems, and methods for performing optical and electrochemical assays and, more particularly, to devices and systems having universal channel circuitry configured to perform optical and electrochemical assays, and methods of performing the optical and electrochemical assays using the universal channel circuitry. The universal channel circuitry is circuitry that has electronic switching capabilities such that any contact pin, and thus any sensor contact pad in a testing device, can be connected to one or more channels capable of taking on one or more measurement modes or configurations (e.g., an amperometric measurement mode or a current drive mode).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/546,725 filed on Aug. 17, 2017, the entirety of which is incorporatedherein by reference.

FIELD OF THE INVENTION

This present invention relates generally to devices, systems, andmethods for performing optical and electrochemical assays and, moreparticularly, to devices and systems having universal channel circuitryconfigured to perform optical and electrochemical assays, and methods ofperforming the optical and electrochemical assays using the universalchannel circuitry.

BACKGROUND OF THE INVENTION

Point-of-care (POC) sample analysis systems are typically based on oneor more re-usable hand-held analyzers (i.e., instruments or readingapparatus) that perform sample tests using a single-use disposabletesting device, e.g., a cartridge or strip that contains analyticalelements, e.g., electrodes or optics for sensing analytes such as pH,oxygen and glucose. The disposable testing device may include fluidicelements (e.g., conduits for receiving and delivering the sample tosensing electrodes or optics), calibrant elements (e.g., aqueous fluidsfor standardizing the electrodes with a known concentration of analyte),and dyes with known extinction coefficients for standardizing optics.The instrument or reading apparatus may contain electrical circuitry andother components for operating the electrodes or optics, makingmeasurements, and performing computations. The instrument or readingapparatus may also have the ability to display results and communicatethose results to laboratory and hospital information systems (LIS andHIS, respectively), for example, via a computer workstation or otherdata management system. Communication between the instrument or readingapparatus and a workstation, and between the workstation and a LIS orHIS, may be via, for example, an infrared link, a wired connection,wireless communication, or any other form of data communication that iscapable of transmitting and receiving electrical information, or anycombination thereof. A notable point-of-care system (The i-STAT® System,Abbott Point of Care Inc., Princeton, N.J.) is disclosed in U.S. Pat.No. 5,096,669, which is incorporated herein by reference in itsentirety. The i-STAT® System comprises one or more disposable testingdevices, operating in conjunction with a hand-held analyzer, forperforming a variety of measurements on biological specimens such asblood.

One benefit of point-of-care sample testing systems is the eliminationof the time-consuming need to send a sample to a central laboratory fortesting. Point-of-care sample testing systems allow a nurse or doctor(user or operator), at the bedside of a patient, to obtain a reliablequantitative analytical result, comparable in quality to that whichwould be obtained in a laboratory. In operation, the nurse selects atesting device with the required panel of tests, draws a biologicalsample from the patient, dispenses the biological sample into thetesting device, optionally seals the testing device, and inserts thetesting device into the instrument or reading apparatus. While theparticular order in which the steps occur may vary between differentpoint-of-care systems and providers, the intent of providing rapidsample test results close to the location of the patient remains thesame. The instrument or reading apparatus then performs a test cycle,i.e., all the other analytical steps required to perform the tests. Suchsimplicity gives the doctor quicker insight into a patient'sphysiological status and, by reducing the turnaround time for diagnosisor monitoring, enables a quicker decision by the doctor on theappropriate treatment, thus enhancing the likelihood of a successfulpatient outcome.

As discussed herein, point-of-care sample testing systems typicallyinclude an instrument or reading apparatus configured to perform sampletests using single-use disposable testing device for the determinationof analytes in biological samples. The type of sample tests performedmay vary and can be implemented using one or more testing devicesincluding, for example, a qualitative or semi-quantitative testingdevice (e.g., lateral flow or microarray assays), a quantitative testingdevice (e.g., an electrochemical assay), or a combined qualitative orsemi-quantitative testing device and a quantitative testing device(e.g., a testing device with both lateral flow or microarray assays andan electrochemical assay). In order to perform the one or more tests theinstrument or reading apparatus may include an optical sensor configuredto process a signal from the qualitative or semi-quantitative testingdevice and/or an electrical connector configured to process a signalfrom the quantitative testing device (see, e.g., U.S. Pat. No.9,194,859, which is incorporated herein by reference in its entirety).In particular, the instrument or reading apparatus may include a firstset of circuitry that hardwires a specific set of pins on the electricalconnector of the instrument or reading apparatus to a specific means ofoperation and amplification for processing the signal from thequalitative or semi-quantitative testing device, and/or a second set ofcircuitry that hardwires a different set of pins on the electricalconnector of the instrument or reading apparatus to a different means ofoperation and amplification for processing the signal from thequantitative testing device.

However, the general use of independent hardwired circuitry ininstruments or reading apparatus for each type of testing device, haslimited the flexibility in positioning different sensors within thetesting device and limited the ability of instruments or readingapparatus to perform multiple types of assays without hardware changes.Hardware changes are typically expensive to implement and can bedifficult to manage from generation to generation of instruments orreading apparatus. Accordingly, the need exists for devices, systems,and methods that are capable of performing multiple types of tests ormeasurements (e.g., optical and electrochemical assays) without havingto use independent hardwired circuitry to perform each type of test ormeasurement.

SUMMARY OF THE INVENTION

In various embodiments, a system is provided for performing multipleassays on a biological sample. The system comprises an analyzercomprising: a cartridge port for mating with a test cartridge, amulti-terminal connector, a processor, memory coupled to the processor,and universal channel circuitry. The universal channel circuitrycomprises a first channel, a second channel, and a third channel. Thesystem further comprises a first test cartridge comprising a lightemitter connected to a first contact and a light detector connected to asecond contact, and a second test cartridge comprising an amperometricelectrode connected to a third contact and a reference electrodeconnected to a fourth contact. The first contact is electricallyconnectable to a first pin of the multi-terminal connector, and thesecond contact is electrically connectable to a second pin of themulti-terminal connector. The third contact is electrically connectableto the first pin of the multi-terminal connector, and the fourth contactis electrically connectable to the second pin of the multi-terminalconnector. The first pin is electrically connectable to the firstchannel, and the second pin is electrically connectable to the secondchannel. when the first test cartridge is inserted into the port of theanalyzer, the first channel comprises circuitry including switches thatare arranged such that the first channel is configured in a currentdriver mode, and the second channel comprises circuitry includingswitches that are arranged such that the second channel is configured ina current measurement mode. When the second test cartridge is insertedinto the port of the analyzer, the first channel is configured in anamperometric measurement mode, and the second channel is configured in areference measurement mode.

In some embodiments, the processor is configured to determine aqualitative, semi-quantitative, or quantitative value proportional to anamount of a target analyte in the biological sample based on the analytesignal. Optionally, the target analyte is selected from the groupconsisting of: human chorionic gonadotropin, glucose, lactate,creatinine, urea, prothrombin time (PT), activated partialthromboblastin time (APTT), activated clotting time (ACT), D-dimer,prostate-specific antigen (PSA), creatine kinase-MB (CKMB), brainnatriuretic peptide (BNP), troponin I (TnI), cardiac troponin (cTnI),human chorionic gonadotrophin, troponin T, troponin C, myoglobin,neutrophil gelatinase-associated lipocalin (NGAL), galectin-3,prostate-specific antigen (PSA), parathyroid hormone (PTH), galectin-3,aspartate aminotransferase (AST), alanine aminotransferase (ALT),albumin, total protein, bilirubin, and alkaline phosphatase (ALP).

In some embodiments, the test cartridge further comprises a mirroredreflector that reflects light from the light emitter through the conduitto the light detector. The mirrored reflector may be at least a portionof a surface of the conduit.

In some embodiments, the first test cartridge further comprises a filterbetween the sample receiving chamber and the conduit, and the filter isconfigured to retain blood cells from the biological sample and permitpassage of plasma. The cartridge port maybe configured to the receivethe first test cartridge and the second test cartridge sequentially.

In various embodiments, a system is provided comprising one or moreprocessors, and memory coupled to the one or more processors, the memoryencoded with a set of instructions configured to perform a processcomprising: receiving an operating state signal from a first testcartridge indicative of a first type of cartridge inserted into ananalyzer; determining that the first type of cartridge is the first testcartridge having a first contact connected to a light emitter and asecond contact connected to a light detector; assigning a first channelto the light emitter via the first contact and a corresponding firstpin; assigning a second channel to the light detector via the secondcontact and a corresponding second pin; switching circuitry of the firstchannel to a current driver mode; switching circuitry of the secondchannel to a current measurement mode; performing an optical analyticaltest using the first channel and the second channel; receiving anoperating state signal from a second test cartridge indicative of asecond type of cartridge inserted into the analyzer; determining thatthe second type of cartridge is the second test cartridge having a firstcontact connected to an amperometric electrode and a second contactconnected to a reference electrode; assigning a first channel to theamperometric electrode via the first contact and another correspondingfirst pin; assigning a second channel to the reference electrode via thesecond contact and another corresponding second pin; switching circuitryof the first channel to an amperometric measurement mode; switchingcircuitry of the second channel to a reference measurement mode; andperforming an electrochemical analytical test using the first channeland the second channel.

In some embodiments, the receiving the operating state signal indicativeof the first type of cartridge and the receiving the operating statesignal indicative of the second type of cartridge are receivedsequentially.

In some embodiments, the first test cartridge is inserted into theanalyzer prior to the second test cartridge being inserted into theanalyzer. Alternatively, the second test cartridge may be inserted intothe analyzer prior to the first test cartridge being inserted into theanalyzer.

In some embodiments, the performing the optical analytical testcomprises: applying, using the first channel, a drive current to thelight emitter; converting, using the second channel, an output signalreceived from the light detector to an analyte signal proportional to anamount light detected by the light detector; and determining aqualitative, semi-quantitative, or quantitative value proportional to anamount of target analyte in a biological sample in the test cartridgebased on the analyte signal. Optionally, the target analyte is selectedfrom the group consisting of: human chorionic gonadotropin, glucose,lactate, creatinine, urea, prothrombin time (PT), activated partialthromboblastin time (APTT), activated clotting time (ACT), D-dimer,prostate-specific antigen (PSA), creatine kinase-MB (CKMB), brainnatriuretic peptide (BNP), troponin I (TnI), cardiac troponin (cTnI),human chorionic gonadotrophin, troponin T, troponin C, myoglobin,neutrophil gelatinase-associated lipocalin (NGAL), galectin-3,prostate-specific antigen (PSA), parathyroid hormone (PTH), galectin-3,aspartate aminotransferase (AST), alanine aminotransferase (ALT),albumin, total protein, bilirubin, and alkaline phosphatase (ALP).

In some embodiments, the test cartridge further comprises a mirroredreflector that reflects light from the light emitter through the conduitto the light detector. The mirrored reflector may be at least a portionof a surface of the conduit

In some embodiments, the first test cartridge further comprises a filterbetween the sample receiving chamber and the conduit, and the filter isconfigured to retain blood cells from the biological sample and permitpassage of plasma.

In some embodiments, the performing the electrochemical analytical testcomprises: applying, using the second channel, a potential to theamperometric electrode with respect to the reference electrode;measuring, using the first channel, a current change across a biologicalspecimen that is proportional to a concentration of another targetanalyte within the biological specimen; and determining theconcentration of the another target analyte within the biologicalspecimen based on the current change across the biological specimen.

In some embodiments, the operating state signal comprises a value of ameasured resistance between contacts of the first test cartridge or thesecond test cartridge and a shorting bar. Alternatively, the operatingstate signal may comprise a value obtained from a barcode located on thefirst test cartridge or the second test cartridge.

In some embodiments, the determining that the first test cartridge hasthe first contact connected to the light emitter and the second contactconnected to the light detector, comprises: identifying, based on avalue of the operating state signal, the first type of cartridge using alook-up table, and obtaining, based on the first type cartridge,information regarding sensors of the first test cartridge from adatabase, wherein the information indicates that the first testcartridge includes an optical sensor that has the light emitterconnected to the first contact and the light detector connected to thesecond contact.

In various embodiments, a system is provided for performing multipleassays on a biological sample. The system comprises an analyzercomprising: a port, a multi-terminal connector, a processor, anduniversal channel circuitry, wherein the universal channel circuitrycomprises a first channel, a second channel, and a third channel; and atest cartridge comprising a light emitter connected to a first contact,a photo detector connected to a second contact, and an amperometricelectrode connected to a third contact. The first contact iselectrically connectable to a first pin of the multi-terminal connector,the second contact is electrically connectable to a second pin of themulti-terminal connector, and the third contact is electricallyconnectable to a third pin of the multi-terminal connector. The firstpin is electrically connectable to the first channel, the second pin iselectrically connectable to the second channel, and the third pin iselectrically connectable to the third channel. The first channelcomprises circuitry including switches that are arranged such that thefirst channel is configured in a current driver mode, the second channelcomprises circuitry including switches that are arranged such that thesecond channel is configured in a current measurement mode, and thethird channel comprises circuitry including switches that are arrangedsuch that the third channel is configured in an amperometric measurementmode.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood in view of the followingnon-limiting figures.

FIG. 1 shows a disposable testing device and instrument in accordancewith various embodiments;

FIG. 2 shows an illustrative architecture of a computing systemimplemented in accordance with various embodiments;

FIGS. 3 and 4A-4J show a testing device or cartridge in accordance withvarious embodiments;

FIG. 5A shows a side view of the fabrication of an electrochemicalsensor chip in accordance with various embodiments;

FIG. 5B shows a side view of the fabrication of an optical sensor chipin accordance with various embodiments;

FIG. 6A shows a sensor chip configuration in accordance with variousembodiments;

FIG. 6B shows a light shield or reflector in accordance with variousembodiments;

FIGS. 7A and 7B show an alternative sensor chip configuration inaccordance with various embodiments;

FIGS. 8A and 8B show an alternative sensor chip configuration inaccordance with various embodiments;

FIGS. 9A and 9B show a transparent substrate in accordance with variousembodiments;

FIGS. 10A-10G show universal channel circuitry in accordance withvarious embodiments; and

FIGS. 11-16 show processes in accordance with various embodiments.

DETAILED DESCRIPTION OF THE INVENTION Introduction

Various embodiments of the present invention are directed to devices,systems, and methods for performing optical and electrochemical assays.For example, FIG. 1 shows an exemplary system 100 that may comprise aself-contained disposable testing device or cartridge 105 and aninstrument or reading apparatus 110 (e.g., an analyzer) that is portableor stationary and battery powered or line powered. In some embodiments,the testing device 105 is a single-use device configured to bedisposable after the single-use. A fluid sample (e.g., whole blood) tobe measured is drawn into a sample receiving chamber via a sample entryorifice 115 in the testing device 105, and the testing device 105 may beinserted into the analyzer 110 through a port 120. The analyzer 110 maycomprise a processor configured to perform processes including themeasurement of analyte concentrations, the measurement of resistances,the control of a temperature of a biological sample, the conversion ofcurrent output to a measurable voltage, and the identification ofanalytes or sets of analytes that a chip is configured to measure.Measurements and determinations performed by the analyzer 110 may beoutput to a display 125 or other output device, such as a printer ordata management system 130 via a port 135 on the analyzer 110 to acomputer port 140. Transmission can be via wired or wirelesscommunication such as a telephone network, Internet connection, Wi-Fi,Bluetooth link, infrared and the like. The sensors 145 (e.g., anelectrochemical sensor and/or an optical sensor) in the testing device105 include a plurality of discrete connector contacts 150 that makeelectrical contact with the analyzer 110 via a multi-terminal connector155 when the testing device 105 is inserted into the port 120. Forexample, the multi-terminal connector 155 may be of the design disclosedin U.S. Pat. No. 4,954,087, which is incorporated herein by reference inits entirety. The analyzer 110 may also be configured to perform amethod for automatic fluid flow compensation in the testing device 105,as disclosed in U.S. Pat. No. 5,821,399, which is also incorporatedherein by reference in its entirety.

In conventional instruments or reading apparatus, the multi-terminalconnector has a linear array of pins, which mate with a linear array ofdiscrete connector contacts in the testing device. A problem associatedwith these conventional instruments or reading apparatus is that eachpin is hardwired to an assigned function, and thus there is limitedflexibility in positioning the different sensors within a cartridge. Forexample, the connector pad of a potassium electrode on a testing deviceneeds to be aligned to one of the potentiometric working electrode pinson the connector. Another limitation of the conventional instruments orreading apparatus is that they only have a limited number of measurementpins (e.g., amperometric pins), and future testing devices may need toperform multiple tests or measurements. For example, a dual immunoassaycartridge, each with its own immuno-reference sensor, may need fouramperometric channels. Consequently, the limitations imposed by thehardwired design of the conventional instruments or reading apparatusadversely affects the capability of the instruments or reading apparatusto perform multiple tests or measurements without hardware changes.

To address these problems, various embodiments described herein aredirected to devices and systems having universal channel circuitryconfigured to perform optical and electrochemical assays (e.g.,amperometric analyte assays, potentiometric analyte assays, orconductometric assays), and methods of performing the optical andelectrochemical assays using the universal channel circuitry. Theuniversal channel circuitry is distinct in that it is not hard wired incertain aspects. Instead, the “universal channel circuitry”, as usedherein, is defined as circuitry that has electronic switchingcapabilities such that any contact pin, and thus any sensor contact padin a testing device, can be connected to one or more channels capable oftaking on one or more measurement modes or configurations (e.g., twelvepotentiometric channels, four amperometric channels, one of twoconductometric channels, etc.). In particular and in accordance withvarious aspects of the present invention, hardwired circuitry typicallyconfigured to operate amperometric, potentiometric, and conductometricsensors independently has been further developed to operateamperometric, potentiometric, and conductometric sensors universally,and additionally operate light emitting diodes (LED) and photodiodes(PD) for performing optical assays in testing devices, as discussed infurther detail herein.

In one embodiment, a system is provided for performing an optical assayon a biological sample. The system includes (i) an analyzer comprising:a port, a multi-terminal connector, a processor, memory coupled to theprocessor, and universal channel circuitry, where the universal channelcircuitry is electrically connected to the multi-terminal connector, and(ii) a test cartridge comprising a plurality of discrete connectorcontacts, a sample receiving chamber fluidically connected to a conduit,and an analyte assay region comprising: a portion of the conduit, alight emitter such as a light emitting diode (LED), and a light sensoror detector such as a photodiode (PD). The test cartridge is insertableinto the port such that the multi-terminal connector is in electricalcontact with the plurality of discrete connector contacts. The memory isencoded with a set of instructions configured to perform the opticalanalyte assay and at least one of: an amperometric analyte assay, apotentiometric analyte assay, and a conductometric assay. In order toperform the optical analyte assay, (i) the universal channel circuitryis electrically connected to the light emitter via at least one of theplurality of discrete connector contacts and the multi-terminalconnector, (ii) the universal channel circuitry is electricallyconnected to the light detector via at least one of the plurality ofdiscrete connector contacts and the multi-terminal connector, (iii) theuniversal channel circuitry is configured to drive the light emitter togenerate light projected into the portion of the conduit, (iv) the lightdetector is configured to convert light received from the portion of theconduit to an output signal, and (v) the universal channel circuitry isconfigured to convert the output signal of the light detector to ananalyte signal proportional to the light received from the portion ofthe conduit. In order to perform at least one of: the amperometricanalyte assay, the potentiometric analyte assay, and the conductometricassay, the universal channel circuitry is electrically connectable to atleast one of: an amperometric electrode, a potentiometric electrode, andconductometric electrode.

Advantageously, these approaches provide devices, systems, and methodswith greater flexibility in testing device design including: (i) thecombination of tests in any give testing device, (ii) the combination oftests on any given sensor chip, (iii) the position of sensors within thetesting device, (iv) extending utility of the analyzers to performvarious types of assays without hardware changes, and (v) increasing thepoint-of-care testing opportunities. In addition, these approaches mayalso reduce the number of different testing device bases (whichaccommodate the sensor chips) used to manufacture all the differenttesting devices for the various test.

System Environment

FIG. 2 is an illustrative architecture of a computing system 200implemented in various embodiments. The computing system 200 is only oneexample of a suitable computing system and is not intended to suggestany limitation as to the scope of use or functionality of the variousembodiments. Also, computing system 200 should not be interpreted ashaving any dependency or requirement relating to any one or combinationof components illustrated in computing system 200.

As shown in FIG. 2, computing system 200 includes a computing device205. The computing device 205 can be resident on a networkinfrastructure such as within a cloud environment, or may be a separateindependent computing device (e.g., a computing device implementedwithin the environment of an analyzer such as analyzer 110 as describedwith respect to FIG. 1)). The computing device 205 may include one ormore input devices 210, one or more output devices 212, a bus 215,processor 220, a storage device 225, a system memory (hardware device)230, and a communication interface 235.

The one or more input devices 210 may include one or more mechanismsthat permit an operator to input information to computing device 205,such as, but not limited to, a touch pad, dial, click wheel, scrollwheel, touch screen, one or more buttons (e.g., a keyboard), mouse, gamecontroller, track ball, microphone, camera, proximity sensor, lightdetector, motion sensors, biometric sensor, and combinations thereof.The one or more output devices 212 may include one or more mechanismsthat output information to an operator, such as, but not limited to,audio speakers, headphones, audio line-outs, visual displays, antennas,infrared ports, tactile feedback, printers, or combinations thereof.

The bus 215 permits communication among the components of computingdevice 205. For example, bus 215 may be any of several types of busstructures including a memory bus or memory controller, a peripheralbus, and a local bus using any of a variety of bus architectures toprovide one or more wired or wireless communication links or paths fortransferring data and/or power to, from, or between various othercomponents of computing device 205.

The processor 220 may be one or more integrated circuits, printedcircuits, controllers, microprocessors, or specialized dedicatedprocessors that include processing circuitry operative to interpret andexecute computer readable program instructions, such as programinstructions for controlling the operation and performance of one ormore of the various other components of computing device 205 forimplementing the functionality, steps, and/or performance of theembodiments discussed herein. In certain embodiments, processor 220interprets and executes the processes, steps, functions, and/oroperations, which may be operatively implemented by the computerreadable program instructions. For example, processor 220 can receive asignal indicative of a type of test cartridge; determine, based on thetype of test cartridge, that the test cartridge has a first contactconnected to a light emitter and a second contact connected to a lightdetector; assign a first channel to the light emitter via the firstcontact and a corresponding first pin; assign a second channel to thelight detector via the second contact and a corresponding second pin;switch the circuitry of the first channel to a current driver mode;switch the circuitry of the second channel to an current measurementmode; apply, using the first channel, a drive current to the lightemitter; convert, using the second channel, an output signal receivedfrom the light detector to a measurable voltage or analyte signalproportional to an amount of light detected by the light detector; anddetermine a qualitative, semi-quantitative, or quantitative valueproportional to an amount of target analyte in the biological sample orspecimen based on the measurable voltage or the analyte signal. In someembodiments, the information obtained or generated by the processor 220,e.g., type of test cartridge, circuit configurations for the channelsincluding whether each switching element should be switched on/off, atally for various operations, output current, look-up tables, potentialto be applied, etc., can be stored in the storage device 225. In certainembodiments, the processor 220 may comprise a thermal controller forcontrolling a temperature of the biological sample or specimen in aportion of a conduit.

In various embodiments, the processor 220 comprises anapplication-specific integrated circuit 240 that includes the universalchannel circuitry 245, and analog to digital signal converter 247. Inother embodiments, the processor 220 is in communication with theapplication-specific integrated circuit 240 that includes the universalchannel circuitry 245. The application-specific integrated circuit 240is an integrated circuit (IC) customized for performing a number offunctions including an analog to digital signal interface, current tovoltage conversion, multiplexing, resistor selection, signalamplification, potential and conductance generation and/or measurement,and the performance of multiple types of assays. The universal channelcircuitry 245 includes circuitry that can be implemented in conjunctionwith computer readable program instructions, data structures, programmodules and other data to switch between various modes or configurations(e.g., a potentiometric mode, an amperometric mode, a conductance mode,an optical mode, etc.) and contribute to the performance of multipletypes of assays.

The storage device 225 may include removable/non-removable,volatile/non-volatile computer readable media, such as, but not limitedto, non-transitory machine readable storage medium such as magneticand/or optical recording media and their corresponding drives. Thedrives and their associated computer readable media provide for storageof the computer readable program instructions, data structures, programmodules and other data for operation of computing device 205. In variousembodiments, storage device 225 may store operating system 250,application programs 255, and/or program data 260. In some embodiments,the application programs 255, and/or program data 260 may include adatabase, index, or table, and algorithms, for example, qualitative,semi-quantitative, or quantitative value algorithms that includecomponents for determining a presence and/or amount of target analyte ina biological specimen or sample, a position determining algorithm fordetermining the location of a biological sample within a test devicebased on detected conductance, and a hematocrit determination algorithmfor determining a hematocrit of a biological sample based on detectedconductance across a biological sample, which provide the instructionsfor execution of processor 220.

The system memory 230 may include one or more storage mediums, includingfor example, non-transitory machine readable storage medium such asflash memory, permanent memory such as read-only memory (“ROM”),semi-permanent memory such as random access memory (“RAM”), any othersuitable type of non-transitory storage component, or any combinationthereof. In some embodiments, an input/output system 265 (BIOS)including the basic routines that help to transfer information betweenthe various other components of computing device 205, such as duringstart-up, may be stored in the ROM. Additionally, data and/or programmodules 270, such as at least a portion of operating system 250,application programs 255, and/or program data 260, that are accessibleto and/or presently being operated on by processor 220, may be containedin the system memory 230.

The communication interface 235 may include any transceiver-likemechanism (e.g., a network interface, a network adapter, a modem, orcombinations thereof) that enables computing device 205 to communicatewith remote devices or systems, such as other analyzers, a hospitalinformation system, a mobile device or other computing devices such as,for example, a server in a networked environment, e.g., cloudenvironment. For example, computing device 205 may be connected toremote devices or systems via one or more local area networks (LAN)and/or one or more wide area networks (WAN) using communicationinterface 235.

As discussed herein, computing system 200 may be configured to performone or more analytical tests (e.g., an optical assay and/or anelectrochemical assay). In particular, computing device 205 may performtasks (e.g., process, steps, methods and/or functionality) in responseto processor 220 executing program instructions contained innon-transitory machine readable storage medium, such as system memory230. The program instructions may be read into system memory 230 fromanother computer readable medium (e.g., non-transitory machine readablestorage medium), such as data storage device 225, or from another devicevia the communication interface 235 or server within or outside of acloud environment. In some embodiments, hardwired circuitry of computingsystem 200 may be used in place of or in combination with the programinstructions to implement the tasks, e.g., steps, methods and/orfunctionality, consistent with the different aspects discussed herein.Thus, the steps, methods and/or functionality disclosed herein can beimplemented in any combination of hardware circuitry and software.

Testing Device or Cartridge

In one embodiment, as shown in FIG. 3, a testing device or cartridge 300(e.g., testing device 105 as described with respect to FIG. 1) comprisesa top portion 305 (e.g., a cover) and a bottom portion 310 (e.g., abase) in which are mounted at least one microfabricated sensor chip 315with electrical contacts and a pouch 320 containing a fluid, e.g., acalibrant fluid, a diluent fluid and/or a wash fluid. At least onesensor chip 315 may be positioned in recessed region 318 and configuredto generate electric signals based on a concentration of specificchemical species in a fluid sample, e.g., a blood sample from a patient.In some embodiments, the composition of the fluid in the pouch 320 isselected from the group consisting of water, calibrant fluid, reagentfluid, control fluid, wash fluid and combinations thereof. A gasket 325may be situated between the top portion 305 and the bottom portion 310to bond them together, and to define and seal several cavities andconduits within the cartridge 300. The gasket 325 may coversubstantially the entire area between the top portion 305 and the bottomportion 310 of the cartridge 300, as shown in FIG. 3, or may belocalized over and between only predetermined structural features, e.g.,at least one sensor chip 315 of the cartridge 300 (not shown). Thegasket 325 may include apertures 330 to enable physical, fluidic and/orgaseous communication between structural features of the top portion 305and the bottom portion 310. The gasket 325 may or may not have anadhesive surface, and may have an adhesive surface on both sidesthereof, i.e., forming a double-sided adhesive layer.

As shown in FIGS. 4A-4J, in some embodiments, the testing device orcartridge 400 (e.g., cartridge 300 as described with respect to FIG. 3)has a housing that comprises a top portion 402 (e.g., a cover) and abottom portion 404 (e.g., a base) formed of rigid and flexible zones ofmaterial. As shown in FIGS. 4A-4J, the rigid zones (non-shaded portions)of the cover 402 and the base 404 respectively are preferably each asingle contiguous zone; however, the molding process can provide aplurality of non-contiguous substantially rigid zones. The flexiblezones (shaded portions) of the cover 402 and the base 404 respectivelyare preferably a set of several non-contiguous zones. For example, theflexible zone around a displaceable membrane may be separate anddistinct from the flexible zone at a closeable sealing member.Alternatively, the flexible zones may comprise a single contiguous zone.

The sensing device or cartridge 400 further comprises a sealable sampleentry port 406 and a closable sealing member 408 for closing the sampleentry port 406, a sample receiving chamber 410 located downstream of thesample entry port 406, a capillary stop 412, an optional filter 413between the sample receiving chamber 410 and a sensor region 414 (i.e.,analyte assay region), and a waste chamber 416 located downstream of thesensor region 414. The filter 413 may be configured to retain bloodcells from a biological sample and permit passage of plasma into thesensor region 414. Preferably, the cross-sectional area of a portion ofthe sample receiving chamber 410 decreases distally with respect to thesample entry port 406. A pouch (e.g., the pouch 320 described withrespect to FIG. 3) may be disposed in a recessed region 420 and in fluidcommunication with a conduit 422 leading to the sensor region 414,optionally via conduit 424. The pouch may be of the design described inU.S. Pat. No. 5,096,669 or, more preferably, in U.S. Pat. No. 8,216,529,both of which are incorporated herein by reference in their entireties.Recessed region 420 preferably includes a spike 425 configured torupture the pouch, upon application of a force upon the pouch, forexample, by reader or analyzer (e.g., analyzer 110 as described withrespect to FIG. 1). Once the pouch is ruptured, the system is configuredto deliver the fluid contents from the pouch into conduit 422. Movementof the fluid into the conduit 422 and to the sensor region 414 and/orwithin the conduit 424 may be effected by a pump, e.g., a pneumatic pumpconnected to the conduit(s) 422 or 424. Preferably, the pneumatic pumpcomprises a displaceable membrane 426 formed by a portion of a flexiblezone 427 of the housing formed over a recessed region or air bladder428. In the embodiment shown in FIGS. 4A-4J, upon repeatedly depressingthe displaceable membrane 426, the device pumps via conduits 429 and 430causing fluid from the ruptured pouch to flow through the conduit 422,optionally into the conduit 424, and over the sensor region 414 viaconduit 431.

The closable sealing member 408, in some embodiments, includes a portionof the rigid zone that forms a sealing member 432, and a portion of theflexible zone that forms a seal 433. The sealing member 408 can rotateabout hinge 434 and engage the seal 433 with the sample entry port 406when in a closed position, thus providing an air-tight seal.Alternatively, an air-tight seal may be formed by contact of twoflexible materials, e.g., a thermoplastic elastomer (TPE) on TPE.Optionally, the sealable sample entry port 406 also includes a vent hole(not shown). In an alternative embodiment, a portion of the rigid zoneforms a sealing member, and a portion of the flexible zone forms aperimeter seal around the sample entry port, whereby the sealing membercan rotate about a hinge and engage the perimeter seal when in a closedposition, thus providing an air-tight seal. Alternatively, the perimeterseal may be formed by contact of two flexible materials. In yet anotherembodiment, the sealing member may include a slidable closure element asdescribed in pending U.S. Pat. No. 7,682,833, the entirety of which isincorporated herein by reference.

The sensor region 414, in some embodiments, contains a sensor arraycomprising one or more sensors for one or more different analytes (orblood tests). For example, the sensor array may include anelectrochemical sensor and/or an optical sensor for one or moredifferent analytes (or blood tests). The electrochemical sensor mayinclude a base sensor or sensing electrode on a substantially planarchip (e.g., a microfabricated sensor chip such as the at least onesensor chip 315 described with respect to FIG. 3) where the sensingelectrode is positioned in conduit 431 for receiving a sample mixed witha reagent. The optical sensor may include one or more light emitters(e.g., LEDs) and one or more light detectors (e.g., PDs) on asubstantially planar chip (in some embodiments the same sensor chip thatincludes the electrochemical sensor) where the one or more lightemitters and one or more light detectors are positioned near the conduit431 for transmitting and receiving light through the conduit 431comprising a sample optionally mixed with reagent. In alternativeembodiments, the sensor array comprises a plurality of sensors for aplurality of different analytes (or blood tests). Accordingly, thecartridge 400 may have one or more sensor regions 414 each with at leastone sensor.

Preferably, at least a portion of the conduit 431 includes a uniformwidth dimension in the range of about 0.1 mm to about 4 mm, and auniform height dimension in the range of about 0.1 mm to about 4 mm. Asused herein, the terms “substantially,” “approximately” and “about” aredefined as being largely but not necessarily wholly what is specified(and include wholly what is specified) as understood by one of ordinaryskill in the art. In any disclosed embodiment, the term “substantially,”“approximately,” or “about” may be substituted with “within [apercentage] of” what is specified, where the percentage includes 0.1, 1,5, and 10 percent.

In various embodiments, the sensor recess 414 comprises a plurality ofLEDs and a plurality of PDs. The plurality of LEDs and the plurality ofPDs may be paired up such that the sensor recess 414 comprises aplurality of paired LEDs and PDs. The plurality of LEDs and PDs orplurality of paired LEDs and PDs may be located at discrete positionswith respect to the conduit 431. In certain embodiments, each pair ofLEDs and PDs is substantially optically isolated from the other pairs ofLEDs and PDs. For example, the pairs of LEDs and PDs may be spaced apredetermined distance from one another and/or include a filteringstructure between one another such that each pair of LEDs and PDs issubstantially optically isolated from the other pairs of LEDs and PDs.

The analytes/properties to which the sensors respond may be selectedfrom among human chorionic gonadotropin, pH, partial pressure CO₂,partial pressure O₂, glucose, lactate, creatinine, urea, sodium,potassium, chloride, calcium, magnesium, phosphate, hematocrit,prothrombin time (PT), activated partial thromboblastin time (APTT),activated clotting time (ACT), D-dimer, prostate-specific antigen (PSA),creatine kinase-MB (CKMB), brain natriuretic peptide (BNP), troponin I(TnI), cardiac troponin (cTnI), human chorionic gonadotrophin, troponinT, troponin C, myoglobin, neutrophil gelatinase-associated lipocalin(NGAL), galectin-3, prostate-specific antigen (PSA), parathyroid hormone(PTH), galectin-3, aspartate aminotransferase (AST), alanineaminotransferase (ALT), albumin, total protein, bilirubin, alkalinephosphatase (ALP), and the like, and combinations thereof. Preferably,the analyte is tested in a liquid sample that is whole blood, howeverother samples can be used including blood, serum, plasma, urine,cerebrospinal fluid, saliva and amended forms thereof. Amendments caninclude dilution, concentration, addition of regents such asanticoagulants and the like. Whatever the sample type, it can beaccommodated by the sample entry port 406 of the cartridge 400.

The cartridge 400 may further comprise a portion 426 of the flexiblezone 436 positioned over the recessed region 420 that is configured forbeing actuated upon like a pump to apply pressure within the recessedregion 420. In some embodiments, the flexible zone 436 may include ageneric symbol description to indicate to the user that pressure shouldnot be applied to the flexible zone 436 by the user. For example, thesymbol may comprise an embossed circle with a crossbar. The portion ofthe flexible zone 436 provides a surface that can accommodate anactuator feature of the analyzer (e.g., analyzer 110 as described withrespect to FIG. 1) to apply a force and burst the underlying pouch inthe recessed region 420. The thickness of the plastic in the flexiblezone 436 may be preferably from about 200 to about 800 μm, for exampleabout 400 μm. Essentially, the flexible zone 436 should be sufficientlythin to flex easily, but sufficiently thick to maintain physicalintegrity and not tear.

Sensor and Chip Designs

In one embodiment, a microfabricated sensor chip (e.g., the at least onesensor chip 315 described with respect to FIG. 3) comprises at least onesensor or transducer (e.g., an electrochemical sensor and/or opticalsensor). For example, the microfabricated sensor chip may comprise anelectrochemical sensor or an optical sensor. Alternatively, themicrofabricated sensor chip may comprise a sensory array including atleast a first sensor (e.g., an electrochemical sensor) and a secondsensor (e.g., an optical sensor). In some embodiments, the sensors maybe fabricated singularly, or as adjacent structures within a sensorarray, on a silicon chip, a plastic, polyester, polyimide, or siliconplanar substrate, a plastic, polyester, polyimide, or silicon substrate,a transparent plastic, polyester, polyimide, or silicon substrate, aprinted circuit board (PCB), and the like.

In various embodiments, one or more of the electrochemical sensors maybe formed as electrodes with gold surfaces coated with a photo definedpolyimide layer that includes openings to define a grid of small goldelectrodes (e.g., a gold microarray electrode) at which an electroactivespecies may be oxidized. For example, wafer-level micro-fabrication of apreferred embodiment of the sensor chip may be achieved as shown in FIG.5A. A non-conducting substrate 500 having a planar top and bottomsurface may be used as a base for the sensor chip. A conducting layer505 may be deposited on the substrate 500 by conventional means, e.g.,screen printing, or micro-fabrication technique known to those of skillin the art to form at least one component (e.g., a microarrayelectrode). The conducting layer 505 may comprise a noble metal such asgold, platinum, silver, palladium, iridium, or alloys thereof, althoughother unreactive metals such as titanium and tungsten or alloys thereofmay also be used, as many non-metallic electrodes of graphite,conductive polymer, or other materials may also be used. Themicrofabricated sensor chip may also comprise an electrical connection510 that connects the electrode to a conductive pin such as a temporary(make and break) electrical connector.

In some embodiments, the one or more of the electrochemical sensors maycomprise an array of 5-10 μm noble metal disks, e.g., 7 μm noble metaldisks, on 15 μm centers. The array of noble metal disks or electrodesmay cover a region, e.g., a circular region, approximately 300 to 900 μmin diameter, optionally 400-800 μm or about 600 μm in diameter, and maybe formed by photo-patterning a thin layer of polyimide or photoresistof thickness up to 1.5 μm over a substrate made from a series of layerscomprising Si,SiO₂,TiW, and/or Au, or combinations thereof. In someembodiments, the electrodes have a working area of about 130,000 to300,000 sq μm (i.e., a microelectrode), the volume of sample directlyover the electrodes may be about 0.1-0.3 μL and the volume of the sampleover the sensor chip may be 1-3 μL. In accordance with these aspects ofthe present invention, the conduit (e.g., the conduit 431 described withrespect to FIG. 4A) in a region of the electrodes (e.g., the one or moresensor recesses 414 described with respect to FIGS. 4A-4J) has a volumeto sensor area ratio of less than about 6 μL, to about 1 square mm.

In various embodiments, one or more of the optical sensors may be formedas one or more light emitters (e.g., LEDs) and one or more lightdetectors (e.g., PDs) on a substantially planar chip (in someembodiments the same sensor chip that includes the electrochemicalsensor). For example, wafer-level micro-fabrication of a preferredembodiment of the sensor chip may be achieved as shown in FIG. 5B. Anon-conducting substrate 500 having a planar top and bottom surface maybe used as a base for the sensor chip. One or more light emitters 515and one or more light detectors 520 may be provided or formed on thesubstrate 500 by conventional means, e.g., a micro-fabrication techniqueknown to those of skill in the art to form at least one emitter anddetector. The microfabricated sensor chip may also comprise anelectrical connection 525 (e.g., an electrical connection comprising aplurality of discrete contacts) that connects the one or more lightemitters 515 and the one or more light detectors 520 to one or moreconductive pins such as a temporary electrical connector.

In some embodiments, the one or more light emitters 515 are comprised ofLEDs. For example, multiple wavelength LEDs, e.g., from 405 nm (nearultra-violet light)-850 nm (near infrared), may be used to cover avariety of tests or a single wavelength LED may be used to increaseillumination power. Typical wavelengths for measurements (deltas ofabsorbance) of various analytes are known and depend on the actual assaydesign, for example 467 and 550 nm for total bilirubin, 600 and 550 nmfor albumin, 550 and 850 nm for total protein, and 400 and 460 nm todistinguish conjugated and unconjugated bilirubin. Selection ofwavelengths such as these may be achieved by one of ordinary skill inthe art. Alternatively, other light sources with or without filters maybe used without departing from the spirit and scope of the presentinvention. The size of the LEDs may be selected to fit with othercomponents (e.g., the conduits or sensor region) of the testing device,e.g., LEDS available as surface mount (SMD) and chip scale packaging(CSP) may be used to fit a variety of testing devices. Typical lowprofile chip LEDs have the industry standard 1.6 mm×0.8 mm footprint,which provides high efficiency light projection and low powerconsumption. LEDs are typically current driven and require voltagesgreater than 2V and current less than 1 mA to turn on. In accordancewith various aspects of the present invention, the drive of the LEDs maybe within the range of 1V-5V and 0.1-1.5 mA, for example substantially3V and 0.5 mA.

In some embodiments, the one or more light detectors 520 are comprisedof a PD(s), e.g., a silicon photo PIN diode(s) having an undopedintrinsic semiconductor region sandwiched between a p-type semiconductorregion and an n-type semiconductor region. The spectral response of thePIN diode may be in the range of 400 nm to 1000 nm. Alternatively, otherlight sensors or detectors with or without filters to control wavelengths may be used without departing from the spirit and scope of thepresent invention This provides the capability to cover a wide spectrumof LED wavelengths. The size of the PIN diode may be selected to fitwith other components (e.g., the conduits or sensor region) of thetesting device, e.g., the PIN diode available as surface mount (SMD) andchip scale packaging (CSP) may be used to fit a variety of testingdevices. Typical a low profile PIN diode has the industry standard 2.0mm×1.25 mm footprint, which provides high efficiency light detection andlow power consumption. In accordance with various aspects of the presentinvention, the sensitivity of the PIN diode may be within the range of0.5 uA/cm²-4 uA/cm², for example substantially 1 uA/cm².

Micro-fabrication techniques (e.g., photolithography and plasmadeposition) may be utilized for construction of the multilayered sensorstructures in confined spaces. For example, methods formicro-fabrication of electrochemical sensors on silicon substrates aredisclosed in U.S. Pat. No. 5,200,051, which is hereby incorporated byreference in its entirety, and include, for example, dispensing methods,methods for attaching substrates and reagents to surfaces includingphotoformed layers, and methods for performing electrochemical assays.

As shown in FIG. 6A, in some embodiments, a microfabricated sensor chip600 includes sensor 605 (e.g., an optical sensor). The sensor 605 may beconstructed of one or more light emitters 610 (e.g., LEDs) and one ormore light detectors 615 (e.g., PDs) that are positioned in an area ofthe sensor chip 600 around a conduit 620. The sensor 605 may beconnected via wirings 625, 630, 632, and 635 to a first conductivecontact 640, a second conductive contact 645, a third conductive contact650, and a fourth conductive contact 652 (e.g., temporary electricalconnector), respectively. The design and arrangement of one or morelight emitters 610, one or more light detectors 615, wirings 625, 630,632, and 635, and/or conductive contacts 640, 645, 650, and 652 on thesensor chip 600 is preferably selected based on printing and performancecharacteristics (e.g., minimize interference between multiple sensors,maximize transmission of light through the conduit and biologicalspecimen, avoidance of interfering light, size constraints, etc.).However, it should be understood to those of ordinary skill in the artthat any design or arrangement for the components is contemplatedwithout departing from the spirit and scope of the present invention.

In certain embodiments, the sensor 605 is configured to measure theabsorption of radiation (i.e., light), as a function of frequency orwavelength, due to the interaction of the radiation with a biologicalsample in the conduit 620. In accordance with these aspects, the sensor605 is constructed of the one or more light emitters 610 arranged totransmit incident light 655 of one or more wavelengths into the conduit620 having the biological sample. Upon the incident light 655 strikingthe sample, photons that match an energy gap of a target analyte or achromatic substance related to a presence of the target analyte presentin the biological specimen are absorbed. Other photons transmit throughthe conduit 620 and biological specimen unaffected. The sensor 605 isfurther constructed of the one or more light detectors 615 arranged tocollect the photons of light 660 transmitted through the conduit 620 andthe biological sample, and convert the transmitted photons of light 660into current. By comparing the attenuation of the transmitted light 660with the incident light 655, an absorption spectrum can be obtained toidentify the presence and/or concentration of the target analyte in thebiological specimen.

The wirings 625, 630, 632, and 635 may be formed with gold surfaces thatare optionally coated with a photo defined polyimide or photoresistlayer such that the wirings 625, 630, 632, and 635 are insulated fromexposure to the environment of the sensor region (e.g., the biologicalsample disposed within the conduit 620). The wirings 625, 630, 632, and635 terminate at the first conductive contact 640, the second conductivecontact 645, the fourth conductive contact 652, and the third conductivecontact 650, respectively (e.g., the discrete connector contacts 150 asdescribed with respect to FIG. 1), which are used to make electricalcontact with a connector (e.g., the multi-terminal connector 155 asdescribed with respect to FIG. 1) in the analyzer (e.g., an i-STAT®cartridge reader as described in U.S. Pat. No. 4,954,087, the entiretyof which is incorporated herein by reference).

As shown in FIGS. 6A and 6B, in some embodiments, a light shield orreflector 665 is provided over and/or around at least a portion ofmicrofabricated sensor chip 600 to reflect the incident light 655towards the one or more light detectors 615 and/or minimize orsubstantially block interfering environmental light (e.g., ambient troom light) from being detected by the one or more light detectors 615.In certain embodiments, the light shield or reflector 665 is positionedover and/or around the entirety of the microfabricated sensor chip 600.In other embodiments, the light shield or reflector 665 is positionedover and/or around the region of the sensor 605 and the conduit 620. Inyet other embodiments, the light shield or reflector 665 is a surface ofthe conduit 620. In addition, the cartridge housing described withrespect to FIGS. 4A-4J may be made of a black or opaque plasticmaterial, wholly or in part, to minimize stray ambient light reachingthe conduit 620 and striking the one or more light detectors 615.Moreover, it should be understood that inserting the cartridge 150 intothe port 120 of the analyzer 110, as shown in FIG. 1, may alsocontribute to assuring that the sensor 605 (e.g., optical sensor) isshielded from stray ambient light.

In some embodiments, a portion of the sensor chip 600 (e.g., a topsurface of the substrate), a wall of the conduit 620 (e.g., the conduit431 described with respect to FIGS. 4A-4J), and/or a wall of the samplechamber (e.g., the sample holding chamber 410 described with respect toFIGS. 4A-4J) can be coated with one or more dry reagents to amend thebiological sample. For example, the sensor chip 600 may include areagent region 667 coated with a reactant and/or substrate for ananalyte of interest. One or more dry reagents that may be used to detectALP are shown in Equation (1):

One or more dry reagents that may be used to detect ALT are shown inEquations (2):

One or more dry reagents that may be used to detect AST are shown inEquations (3):

One or more dry reagents that may be used to detect bilirubin are shownin Equations (4):

and

One or more dry reagents that may be used to detect total protein areshown in Equations (5):

In various embodiments, the reagent region 667 may be defined by acontainment ring structure 668. In some embodiments, the containmentring structure 668 is a hydrophobic ring of polyimide or anotherphotolithographically produced layer. A microdroplet or severalmicrodroplets (approximately 5-40 nL in size) or a series of about a 100nanodroplets (approximately 50 to 1000 pL in size) containing the one ormore dry reagents in some form may be dispensed or printed on thesurface of the sensor chip 600. The photodefined ring structure 668contains this aqueous droplet allowing the reagent region 667 to belocalized to a precision of a few microns. The reagent region 667 can bemade from 0.03 to approximately 2 mm² in size. The upper end of thissize is limited by the size of the conduit and sensor chip 700 inpresent embodiments, and is not a limitation of the invention.

The biological sample or a fluid may be passed at least once over thedry reagent, e.g., the reagent region 667 to dissolve the reagent withinthe biological sample or fluid. Within a segment of the biologicalsample or fluid, the reagent can be preferentially dissolved andconcentrated within a predetermined region of the segment. This isachieved through control of the position and movement of the segment.Thus, for example, if only a portion of a segment, such as the leadingedge, is reciprocated over the reagent, then a high local concentrationof the reagent can be achieved close to the leading edge. Alternatively,if a homogenous distribution of the reagent is desired, for example if aknown concentration of a reagent is required for a quantitativeanalysis, then further reciprocation of the sample or fluid will resultin mixing and an even distribution.

In certain embodiments, the universal channel circuitry of the analyzerapplies a drive current (e.g., a voltage greater than 2V and a currentless than 1 mA) via the first conductive contact 640 to the one or morelight emitters 610 of the sensor 605, and measures output current fromthe one or more light emitters 610 via the second conductive contact645. The output current is channeled from the second conductive contact645 into the universal channel circuitry. Feedback resistor(s) of theuniversal channel circuitry set a nominal range of 0.5 mA to 4 mA, forexample substantially 2 mA, which can provide over 1 mA at up to 4 V.The feedback resistor(s) are able to establish a constant current tocontinually drive the one or more light emitters 610 via the firstconductive contact 640 for a predetermined period of time. The one ormore light detectors 615 channel output current (i.e., the currentconverted from the photons of light 660 received from the one or morelight emitters 610) to the third conductive contact 650. The fourthcontact 652 provides a return path. The output current is channeled fromthe third conductive contact 650 into the universal channel circuitryand converted to a measurable voltage proportional to the amount oflight detected by the one or more light detectors 615. The processor(e.g., the processor 220 described with respect to FIG. 2) converts themeasurable voltage to a qualitative, semi-quantitative, or quantitativevalue proportional to an amount of target analyte in the biologicalspecimen.

In various embodiments, the sensor chip 600 may further include aconductometric sensor (e.g., hematocrit sensors). The conductometricsensor is configured to determine biological sample arrival and/ordeparture at the sensor 605. More specifically, the conductometricsensor lies perpendicular to a length of the conduit 620, and anelectrical resistance between pairs of electrodes for the conductometricsensor may be used to monitor a relative position of a fluid front ofthe biological sample. For example, at the extremes, an open circuitreading may indicate that the biological sample has been pushed offsensor 605 and a closed circuit reading may indicate the sensor 605 iscovered with the biological sample.

As shown in FIG. 6A, the conductometric sensor may comprise at least twoelectrodes 670 and 675 (i.e., electrode pair) positioned downstream andupstream of the one or more light emitters 610 and one or more lightdetectors 615, respectively. The electrodes 670 and 675 may be connectedvia wirings 680 and 685 to a first conductive contact such as the secondconductive contact 645, which may function as a conductometric low pin,and a second conductive contact such as the fourth conductive contact652, which may function as an alternating current source orconductometric high pin, respectively. The wirings 680 and 685 may beformed with a gold surface that is coated with a photo defined polyimideor photoresist layer such that the wirings 680 and 685 are insulatedfrom exposure to the biological sample disposed within the conduits. Assuch, in some embodiments, the biological sample or fluid reaches asensing region 695 after passing over the electrode 670, then thebiological sample subsequently departs the sensing region 695 afterpassing over the electrode 675.

As shown in FIGS. 7A and 7B, in alternative embodiments, amicrofabricated sensor chip 700 includes a plurality of optical sensors705 ¹, 705 ², . . . 705 ^(N). Each sensor 705 may be constructed of oneor more light emitters 710 (e.g., LEDs) and one or more light detectors715 (e.g., PDs). As shown in FIG. 7A, in some embodiments, the pluralityof plurality of optical sensors 705 ¹, 705 ², . . . 705 ^(N) may befabricated as adjacent structures in an area of the sensor chip 700 near(e.g., below, above, or adjacent) a conduit 720. However, in order foreach sensor 705 to accurately detect a qualitative, semi-quantitative,or quantitative value proportional to an amount of target analyte in thebiological specimen, it may be beneficial in certain embodiments toposition each sensor 705 in optically distinct regions. For example, afirst sensor 705 ¹ may generate light of a first wavelength using one ormore light emitters 710 ¹ that is detected by one or more lightdetectors 715 ¹, and a second sensor 705 ² may generate light of asecond wavelength (same or different from the first wavelength) usingone or more light emitters 710 ² that is detected by one or more lightdetectors 715 ². In order to ensure that the incident light and thetransmitted light from the first sensor 705 ¹ do not interfere with thesecond sensor 705 ², and vice versa, the first sensor 705 ¹ and thesecond sensor 705 ² may be spaced apart from one another into opticallydistinct regions by a predetermined distance. In certain embodiments,the first sensor 705 ¹ and the second sensor 705 ² are spaced apart fromone another by a predetermined distance “x”, which is at least 0.3 mm,preferably at least 0.6 mm.

As shown in FIG. 7B, in other embodiments, the plurality of opticalsensors 705 ¹, 705 ², . . . 705 ^(N) may be fabricated in separate areasof the sensor chip 700 near (e.g., below, above, or adjacent) respectiveconduits 720. However, in order for each sensor 705 to accurately detecta qualitative, semi-quantitative, or quantitative value proportional toan amount of target analyte in the biological specimen, it may bebeneficial in certain embodiments to position each sensor 705 inoptically distinct regions. For example, a first sensor 705 ¹ positionednear (e.g., below, above, or adjacent) a first conduit 720 ¹ maygenerate light of a first wavelength using one or more light emitters710 ¹ that is detected by one or more light detectors 715 ¹, and asecond sensor 705 ² near (e.g., below, above, or adjacent) a secondconduit 720 ² may generate light of a second wavelength (same ordifferent from the first wavelength) using one or more light emitters710 ² that is detected by one or more light detectors 715 ². In order toensure that the incident light and transmitted light from the firstsensor 705 ¹ do not interfere with the second sensor 705 ², and viceversa, the first sensor 705 ¹ and the second sensor 705 ² may be spacedapart from one another into optically distinct regions by apredetermined distance. In certain embodiments, the first sensor 705 ¹and the second sensor 705 ² are spaced apart from one another by apredetermined distance “x”, which is at least 0.5 mm, preferably atleast 0.9 mm.

In certain embodiments, the first sensor 705 ¹ may be connected viawirings 725, 730, and 735 to a first conductive contact 740, a secondconductive contact 745, and a third conductive contact 750 (e.g.,temporary electrical connector), respectively. Additionally, the secondsensor 705 ² may be connected via wirings 755, 760, and 765 to a firstconductive contact 770, a second conductive contact 775, and a thirdconductive contact 780 (e.g., temporary electrical connector),respectively. The design and arrangement of the first sensor 705 ¹, thesecond sensor 705 ², the wirings 725, 730, 735, 755, 760, and 765,and/or conductive contacts 740, 745, 750, 770, 775, and 780 on thesensor chip 700 is preferably selected based on printing and performancecharacteristics (e.g., minimize interference between multiple sensors,maximize transmission of light through the conduit and biologicalspecimen, avoidance of interfering light, size constraints, etc.).However, it should be understood to those of ordinary skill in the artthat any design or arrangement for the sensors is contemplated withoutdeparting from the spirit and scope of the present invention.Furthermore, although it is shown in FIGS. 7A and 7B that the secondsensor 705 ² is placed downstream from the first sensor 705 ¹, it shouldbe understood that alternative embodiments of the present invention arecontemplated, for example, having the second sensor 705 ² placedupstream from the first sensor 705 ¹.

For the sake of brevity, the additional structures and processesdescribed with respect sensor chip 600 in FIGS. 6A and 6B are notrepeated here. However, it should be understood to those of ordinaryskill in the art that the additional structures and processes may beincluded with respect to sensor chip 700, and any design or arrangementfor the additional structures and processes is contemplated withoutdeparting from the spirit and scope of the present invention.

As shown in FIGS. 8A and 8B, in alternative embodiments, amicrofabricated sensor chip 800 includes a first sensor 805 (e.g., anoptical sensor) and optionally a second sensor 810 (e.g., anamperometric sensor). The first sensor 805 may be constructed with oneor more light emitters (e.g., LEDs) and one or more light detectors(e.g., PDs) in a first area of the sensor chip 800, as similarlydescribed with respect to FIG. 6A. The second sensor 810 may beconstructed with an array of metal disks or electrodes that cover aregion in a second area of the sensor chip 800. The first sensor 805 andthe second 810 may be fabricated as adjacent structures, respectively,on sensor chip 800. However, in order for the sensor chip 800 toaccurately detect a qualitative, semi-quantitative, or quantitativevalue proportional to an amount of target analyte in the biologicalspecimen, the first sensor 805 and the second sensor 810 may be spacedapart from one another at a predetermined distance “x”. For example, thefirst sensor 805 may be spaced at least 0.3 mm, preferably at least 0.6mm from the second sensor 810.

As shown in FIG. 8A, in some embodiments, the first sensor 805 may beconnected via wirings 815, 817, and 820 to a first conductive contact822, a second conductive contact 825, and a third conductive contact 827(e.g., temporary electrical connector), respectively, and the secondsensor 810 may be connected via wiring 830 to a fourth conductivecontact 832 (e.g., temporary electrical connector). In some embodiments,the first sensor 805 may be configured as an optical sensor and thesecond sensor 810 may be configured as electrochemical sensor both ofwhich are formed on the single sensor chip 800 and positioned near orwithin one or more conduits of the point of care test cartridge.Although it is shown in FIG. 8A that the second sensor 810 is placeddownstream from the first sensor 805, it should be understood thatalternative embodiments of the present invention contemplate otherarrangements such as having the second sensor 810 placed upstream fromthe first sensor 805.

As shown in FIG. 8B, in other embodiments, the first sensor 805 may beconnected via wirings 815, 817, and 820 to a first conductive contact822, a second conductive contact 825, and a third conductive contact 827(e.g., temporary electrical connector), respectively, and the secondsensor 810 may be connected via wiring 830 to the third conductivecontact 827 (e.g., temporary electrical connector). In some embodiments,the first sensor 805 may be configured as an optical sensor and thesecond sensor 810 may be configured as electrochemical sensor both ofwhich are formed on the single sensor chip 800 and positioned near orwithin one or more conduits of the point of care test cartridge.Although it is shown in FIG. 8B that the second sensor 810 is placeddownstream from the first sensor 805, it should be understood thatalternative embodiments of the present invention contemplate having thesecond sensor 810 placed upstream from the first sensor 805.

The first sensor 805 may be constructed of one or more light emitters835 (e.g., LEDs) and one or more light detectors 840 (e.g., PDs) thatare positioned in a first area of the sensor chip 800 and the secondsensor 810 may be constructed with an array of metal disks or electrodesthat cover a circular region in a second area of the sensor chip 800.The design and arrangement of the first and second sensors 805 and 810on the sensor chip 800 are preferably selected based on printing andperformance characteristics for each of the first and second sensors 805and 810. However, it should be understood to those of ordinary skill inthe art that any design or arrangement for the sensors is contemplatedwithout departing from the spirit and scope of the present invention.Furthermore, although the first and second sensors 805 and 810 in theexample in FIGS. 8A and 8B are described herein as optical andamperometric sensors, other sensors can be used. For example, apotentiometric sensor may be used for the detection of ionic speciessuch as Na+ or K+.

In various embodiments, the first sensor 805 is an optical sensorpositioned around a conduit 845. The first sensor 805 may be configuredto measure the absorption of radiation (i.e., light), as a function offrequency or wavelength, due to the interaction of the radiation with abiological sample in the conduit 845. In accordance with these aspects,the first sensor 805 may be constructed of the one or more lightemitters 835 arranged to transmit incident light 847 of one or morewavelengths into the conduit 845 having the biological sample. Upon theincident light 847 striking the sample, photons that match an energy gapof a target analyte or a chromatic substance related to a presence ofthe target analyte present in the biological specimen are absorbed.Other photons transmit through the conduit 845 and biological specimenunaffected. The first sensor 805 may be further constructed of the oneor more light detectors 845 that are arranged to collect the photons oflight 850 transmitted through the conduit 845 and the biological sample,and convert the transmitted photons into current. By comparing theattenuation of the transmitted light 850 with the incident light 847, anabsorption spectrum can be obtained to identify the presence and/orconcentration of the target analyte in the biological specimen.

The wirings 815, 817, and 820 may be formed with gold surfaces that areoptionally coated with a photo defined polyimide or photoresist layersuch that the wirings 815, 817, and 820 are insulated from exposure tothe environment of the sensor region (e.g., the biological sampledisposed within the conduit 845). The wirings 815, 817, and 820terminate at the first conductive contact 822, the second conductivecontact 825, and the third conductive contact 827, respectively (e.g.,the discrete connector contacts 150 as described with respect to FIG.1), which are used to make electrical contact with a connector (e.g.,the multi-terminal connector 155 as described with respect to FIG. 1) inthe analyzer (e.g., an i-STAT® cartridge reader as described in U.S.Pat. No. 4,954,087, the entirety of which is incorporated herein byreference).

In some embodiments, a light shield or reflector 855 may be providedover and/or around at least a portion of microfabricated sensor chip 800to reflect the incident light 847 towards the one or more lightdetectors 840 and/or minimize or substantially block interferingenvironmental light (e.g., ambient t room light) from being detected bythe one or more light detectors 840. In certain embodiments, the lightshield or reflector 855 is positioned over and/or around the entirety ofthe microfabricated sensor chip 800. In other embodiments, the lightshield or reflector 855 is positioned over and/or around the region ofthe first sensor 805 and the conduit 845. In addition, the cartridgehousing described with respect to FIGS. 4A-4J may be made of a black oropaque plastic material, wholly or in part, to minimize stray ambientlight reaching the conduit and striking the one or more light detectors840. Moreover, it should be understood that inserting the cartridge 150into the port 120 of the analyzer 110, as shown in FIG. 1, may alsocontribute to assuring that the first sensor 805 (e.g., optical sensor)is shielded from stray ambient light.

In some embodiments, a portion of the sensor chip 800 (e.g., a topsurface of the substrate), a wall of the conduit 845 (e.g., the conduit431 described with respect to FIGS. 4A-4J), and/or a wall of the samplechamber (e.g., the sample holding chamber 410 described with respect toFIGS. 4A-4J) can be coated with one or more dry reagents to amend thebiological sample for an optical assay. For example, the sensor chip 800may include a reagent region 857 coated with a reactant and/or substratefor an analyte of interest. The one or more dry reagents suitable foroptical assays for total protein, AST, ALT, ALP, and bilirubin aredescribed with respect to FIG. 6A.

In various embodiments, the reagent region 857 may be defined by acontainment ring structure 858. In some embodiments, the containmentring structure 858 is a hydrophobic ring of polyimide or anotherphotolithographically produced layer. A microdroplet or severalmicrodroplets (approximately 5-40 nL in size) or a series of about a 100nanodroplets (approximately 50 to 1000 pL in size) containing the one ormore dry reagents in some form may be dispensed or printed on thesurface of the sensor chip 800. The photodefined ring structure 858contains this aqueous droplet allowing the reagent region 857 to belocalized to a precision of a few microns. The reagent region 857 can bemade from 0.03 to approximately 2 mm² in size. The upper end of thissize is limited by the size of the conduit and sensor chip 800 inpresent embodiments, and is not a limitation of the invention.

In certain embodiments, the universal channel circuitry of the analyzerapplies a drive current (e.g., a voltage greater than 2V and a currentless than 1 mA) via the first conductive contact 822 to the one or morelight emitters 835 of the sensor 805, and measures output current fromthe one or more light emitters 835 via the second conductive contact825. The output current is channeled from the second conductive contact825 into the universal channel circuitry. Feedback resistor(s) of theuniversal channel circuitry set a nominal range of 0.5 mA to 4 mA, forexample substantially 2 mA, which can provide over 1 mA at up to 4 V.The feedback resistor(s) are able to establish a constant current tocontinually drive the one or more light emitters 835 via the firstconductive contact 822 for a predetermined period of time. The one ormore light detectors 840 channel output current (i.e., the currentconverted from the photons of light 850 received from the one or morelight emitters 835) to the third conductive contact 827. The outputcurrent is channeled from the third conductive contact 827 into theuniversal channel circuitry and converted to a measurable voltageproportional to the amount of light detected by the one or more lightdetectors 840. The processor converts the measurable voltage to aqualitative, semi-quantitative, or quantitative value proportional to anamount of target analyte in the biological specimen.

The second sensor 810 may be formed as electrodes with gold surfacesthat are exposed (e.g., no polyimide or photoresist covering) to theinside environment of the conduit 845 and configured to directly contactthe biological sample disposed within the conduit 845. The wiring 830may be formed with a gold surface that is coated with a photo definedpolyimide or photoresist layer such that the wiring 830 is insulatedfrom exposure to the biological sample disposed within the conduit 845.The wiring 830 may be formed comprising a containment ring structure859. In some embodiments, the containment ring structure 859 may beconfigured to contain capture antibodies immobilized on or near thesurface of the electrodes. For example, the capture antibodies may bedeposited onto at least a portion of the second sensor 810 within thecontainment ring structure 859. As shown with respect to FIG. 8A, thewiring 830 terminates at the third conductive contact 827 (e.g., one ofthe discrete connector contacts 150 as described with respect to FIG.1), which is used to make electrical contact with the connector (e.g.,the multi-terminal connector 155 as described with respect to FIG. 1) inthe analyzer. Alternatively, as shown with respect to FIG. 8B, thewiring 830 terminates at the fourth conductive contact 832 (e.g., one ofthe discrete connector contacts 150 as described with respect to FIG.1), which is used to make electrical contact with the connector (e.g.,the multi-terminal connector 155 as described with respect to FIG. 1) inthe analyzer.

In various embodiments, the second sensor 810 is an immunosensorpositioned in the conduit 845 for receiving a biological sample mixedwith an antibody-enzyme conjugate that is configured to bind to a targetanalyte within the biological sample. The second sensor 810 may beconfigured to detect an enzymatically produced electroactive species(e.g., 4-aminophenol) from the reaction of a substrate (e.g.,4-aminophenylphosphate) with the antibody-enzyme conjugate (e.g., one ormore antibodies bound to alkaline phosphatase (ALP)). In accordance withthese aspects, the second sensor 810 contains a capture region orregions 860 coated with capture antibodies that are configured to bindto a target analyte bound to an antibody-enzyme conjugate. The captureregion 860 may be defined by the containment ring structure 859. In someembodiments, the containment ring structure 859 is a hydrophobic ring ofpolyimide or another photolithographically produced layer. Amicrodroplet or several microdroplets (approximately 5-40 nL in size)containing capture antibodies in some form, for example bound to beadsor microspheres, may be dispensed on the surface of the second sensor810. The photodefined ring structure 859 contains this aqueous dropletallowing the capture region 860 to be localized to a precision of a fewmicrons. The capture region 860 can be made from 0.03 to approximately 2mm² in size. The upper end of this size is limited by the size of theconduit 845 and sensor chip 800 in present embodiments, and is not alimitation of the invention.

In some embodiments, a portion of the sensor chip 800 (e.g., a topsurface of the substrate), a wall of the conduit 845 (e.g., the conduit431 described with respect to FIGS. 4A-4J), and/or a wall of the samplechamber (e.g., the sample holding chamber 410 described with respect toFIGS. 4A-4J) can be coated with one or more dry reagents to amend thebiological sample for an electrochemical assay. For example, the sensorchip 800 may include a reagent region 865 coated with an antibody-enzymeconjugate for an analyte of interest. The reagent region 865 may bedefined by a containment ring structure 870. In some embodiments, thecontainment ring structure 870 is a hydrophobic ring of polyimide oranother photolithographically produced layer. A microdroplet or severalmicrodroplets (approximately 5-40 nL in size) or a series of about a 100nanodroplets (approximately 50 to 1000 pL in size) containing theantibody-enzyme conjugate in some form may be dispensed or printed onthe surface of the sensor chip 800. The photodefined ring structure 870contains this aqueous droplet allowing the reagent region 865 to belocalized to a precision of a few microns. The reagent region 865 can bemade from 0.03 to approximately 2 mm² in size. The upper end of thissize is limited by the size of the conduit and sensor chip 800 inpresent embodiments, and is not a limitation of the invention.

The biological sample or a fluid may be passed at least once over thedry reagent, e.g., the reagent region 865 to dissolve the reagent withinthe biological sample or fluid. Reagents used to amend biologicalsamples or fluid within the cartridge may include the antibody-enzymeconjugate, magnetic beads coated with capture antibodies, or blockingagents that prevent either specific or non-specific binding reactionsamong assay compounds. Within a segment of the biological sample orfluid, the reagent can be preferentially dissolved and concentratedwithin a predetermined region of the segment. This is achieved throughcontrol of the position and movement of the segment. Thus, for example,if only a portion of a segment, such as the leading edge, isreciprocated over the reagent, then a high local concentration of thereagent can be achieved close to the leading edge. Alternatively, if ahomogenous distribution of the reagent is desired, for example if aknown concentration of a reagent is required for a quantitativeanalysis, then further reciprocation of the sample or fluid will resultin mixing and an even distribution.

In certain embodiments, the universal channel circuitry of the analyzerapplies a potential via the fourth conductive contact 832 (FIG. 8A) orthe third conductive contact 827 (FIG. 8B) or to the second sensor 810and a reference electrode, and measures current changes generated byoxidation current from the substrate as an electrochemical signal. Theelectrochemical signal being proportional to the concentration of theanalyte in the biological sample. The second sensor 810 may have anapplied potential of approximately +0 mV to 90 mV, e.g., 60 mV versusthe reference electrode and, in another preferred embodiment, the secondsensor 810 has an applied potential of approximately +40 mV versus thereference electrode. The signal generated by the enzyme reaction productat approximately +10 mV is distinguishable from the signal generated bythe unreacted substrate at approximately +200 mV. It should be notedthat the exact voltages used to amperometrically detect the substrateand the analyte will vary depending on the chemical structure of thesubstrate. It is important that the difference in the voltages used todetect the substrate be great enough to prevent interference between thereadings.

In various embodiments, the sensor chip 800 may further include one ormore conductometric sensors 867 (e.g., hematocrit sensors). The one ormore conductometric sensors 867 are configured to determine biologicalsample arrival and/or departure at the reagent regions 857 and 865 andbiological sample arrival and/or departure at the first and secondsensors 805 and 810. More specifically, the one or more conductometricsensors 867 lie perpendicular to a length of the conduit 845 or sensorconduit, and an electrical resistance between pairs of electrodes forthe sensor may be used to monitor a relative position of a fluid frontof the biological sample. For example, at the extremes, an open circuitreading may indicate that the biological sample has been pushed off thereagent region 857 or 865 and a closed circuit reading may indicate thereagent region 857 or 865 is covered with the biological sample.

As shown in FIGS. 8A and 8B, the one or more conductometric sensors 867may comprise at least two electrodes 875 and 880 (i.e., electrode pair)(optionally a third electrode 882 as shown in FIG. 8A). The electrode875 may be positioned downstream of the first sensor 805 and upstreamfrom the reagent region 865, and the electrode 880 may be positiondownstream of the reagent region 865 and upstream of the second sensor810. As shown in FIG. 8A, the electrodes 875 and 880 may be connectedvia wirings 885 and 890 to a fifth conductive contact 892, whichfunctions as a conductometric low pin, and a sixth conductive contact893, which functions an alternating current source or conductometrichigh pin, respectively. Alternatively, as shown in FIG. 8B, theelectrodes 875 and 880 may be connected via wirings 885 and 890 to thefirst conductive contact 822, which function as a conductometric lowpin, and a fourth conductive contact 895, which functions as analternating current source or conductometric high pin, respectively. Thewirings 885 and 890 may be formed with a gold surface that is coatedwith a photo defined polyimide or photoresist layer such that thewirings 885 and 890 are insulated from exposure to the biological sampledisposed within the conduits. As such, in some embodiments, thebiological sample or fluid reaches the reagent region 865 afterdeparting the first sensor 805 and passing over the electrode 875, thenthe biological sample subsequently arrives at the second sensor 810after departing the reagent region 865 and passing over the electrode880.

As shown in FIGS. 9A and 9B, in some embodiments, a microfabricatedsensor chip 900 includes sensor 905 (e.g., an optical sensor) disposedbelow the substrate 910 (e.g., substrate 500 described with respect toFIG. 5B). The sensor 905 may be constructed of one or more lightemitters 915 (e.g., LEDs) and one or more light detectors 920 (e.g.,PDs) that are positioned in an area of the sensor chip 900 below aconduit 925. The sensor 905 may be connected via wirings to conductivecontacts 930. In order for the incident light 935 generated by the oneor more light emitters 915 to be transmitted into the conduit 925 havingthe biological sample, the substrate 910 may be formed of a transparentmaterial, e.g., a transparent plastic or polyester substrate such aspolydimethylsiloxane (PDMS), a liquid transparent silicone polymer. Uponthe incident light 935 striking the sample, photons that match an energygap of a target analyte or a chromatic substance related to a presenceof the target analyte present in the biological specimen are absorbed.Other photons of light 940 transmit through the conduit 925 andbiological specimen unaffected and are reflected back to the one or moredetectors 920 via a light shield or reflector 945. The one or more lightdetectors 920 are arranged to collect the photons of light 940transmitted through the conduit 925, the biological sample, and thesubstrate 910. The one or more detectors 920 converts the transmittedphotons of light 940 into current.

While some embodiments are disclosed herein with respect to certaintypes of sensors (e.g., optical, electrochemical, and conductometricsensors) being electrically connected to certain pins, this is notintended to be restrictive. Instead, it should be understood to those ofordinary skill in the art that any design or arrangement for the sensorsand pins is contemplated without departing from the spirit and scope ofthe present invention. For example, the universal channel circuitry isconfigured in such a manner that any pin and connector connection can beused as a channel for optical, amperometric, conductometric, and/orpotentiometric measurements, as discussed in detail herein.

Universal Channel Circuitry

In various embodiments, the computing device (e.g., computing device 205described with respect to FIG. 2 as being resident on a networkinfrastructure or within the environment of the analyzer) includesuniversal channel circuitry. The universal channel circuitry includeselectronic switching capabilities such that any contact pin, and thusany sensor contact pad in a testing device, can be connected to one ormore measurement channels (e.g., potentiometric, amperometric,conductometric, etc.). As shown in FIG. 10A, the universal channelcircuitry 1000 may comprise any number n of channels 1005 (e.g., 18channels) that can be applied to any one of a number m of contact pinson the multi-terminal connector. The channels 1005 can be applied to thecontact pins in combination, activated, and/or deactivated as sodesired.

As further shown in FIGS. 10 A and 10B, each channel 1005 includescircuitry 1010 that can be switched between various modes orconfiguration using the one or more switches 1015 and computer readableprogram instructions, data structures, program modules and/or other datastored within the memory (e.g., storage device 225 as described withrespect to FIG. 2) of the analyzer. For example, any channel 1005 iscapable of being potentiometric, amperometric, conductometric, groundetc., and in some embodiments all channels are defaulted to ground uponpower-up or reset of the analyzer. In some embodiments, any channel iscapable of being an amperometric channel having circuitry 1010 switchedinto a amperometric measurement mode as configuration 1020 (the grayedout circuitry being circuitry not used or switched off in theamperometric measurement mode), as shown in FIG. 10C. As should beunderstood, the amperometric measurement mode and an optical sensorcurrent measurement mode use the same channel configuration 1020 inorder to perform both amperometric assays and optical assays. Moreover,any channel is capable of being a potentiometric channel, and in someembodiments the circuitry 1010 is switched into a potentiometricmeasurement mode or configuration 1030 (the grayed out circuitry beingcircuitry not used or switched off in the potentiometric measurementmode), as shown in FIG. 10D. In these modes or configurations, thechannels 1005 are primarily configured to measure currents and voltagesprovided by optical, amperometric, and potentiometric sensors.

In accordance with various aspects of the present invention, theuniversal channel circuitry 1000 is configured to provide conductometricmeasurements between at least two channels. For example, any channel1005 (A) may be assigned to a conductometric high electrode of a testingdevice via a first pair of pins and contacts and any other channel 1005(B) may be assigned to a conductometric low electrode of a testingdevice via a second pair of pins and contacts. The circuitry 1010 ofchannel 1005 (A) may be switched into a high conductometric measurementmode or configuration 1035, and the circuitry 1010 of channel 1005 (B)may be switched into a low conductometric measurement mode orconfiguration 1037 (the grayed out circuitry being circuitry not used orswitched off in the low and high conductometric measurement modes orconfigurations), respectively as shown in FIG. 10E. The high and lowconductometric measurement modes or configurations 1035 and 1037 can beenabled or disabled from channels 1005 (A) and (B) at any time afterpower-up such as upon insertion and identification of a type of testingdevice inserted into the analyzer, or relocated to other channels asnecessary. In some embodiments, the conductance functionality isdesigned using a synchronous detection method that is advantageouslyless sensitive to parasitic capacitance. For example, the alternatingcurrent stimulus may be generated from a well-controlled constantalternating current circuit that ensures high linearity with load.

In accordance with other aspects of the present invention, the universalchannel circuitry 1000 is configured to provide multiple electrode(e.g., three electrode) or sensor capability. For example, any channel1005 (A) may be assigned to a counter electrode 1040 of a testing device1042 via a first pair of pins and contacts 1043, any other channel 1005(B) may be assigned to a reference electrode 1045 of the testing device1042 via second pair of pins and contacts 1047, and any other channel1005(C) may be assigned to a working electrode 1050 of the testingdevice 1042 via a third pair of pins and contacts 1052, as shown in FIG.10F. The circuitry 1010 of channel 1005 (A) may be switched into countermeasurement mode by enabling Sw_M and Sw_H and other switches disabled,the circuitry 1010 of channel 1005 (B) may be switched into referencemeasurement mode by enabling Sw_M and Sw_I and other switches disabled,and the circuitry 1010 of channel 1005 (C) may be switched intoamperometric measurement mode or configuration 1020. The countermeasurement mode, the reference measurement mode, and the amperometricmeasurement mode or configuration 1020 can be enabled or disabled fromchannels 1005 (A), (B) and (C) at any time after power-up such as uponinsertion and identification of a type of testing device inserted intothe analyzer, or relocated to other channels as necessary.

In accordance with other aspects of the present invention, the universalchannel circuitry 1000 is configured to provide for optical sensorcapability (e.g., as describe with reference to FIG. 6A). For example,as shown in FIG. 10G, any channel 1005 (A) may be assigned to one ormore light emitters 1060 of a testing device 1062 via a first pair ofpins and contacts 1063, any other channel 1005 (B) may be assigned tothe to one or more light emitters 1060 and/or one or more lightdetectors 1067 of the testing device 1062 via a second pair of pins andcontacts 1065, and any other channel 1005 (C) may be assigned to the oneor more light detectors 1067 of the testing device 1062 via a third pairof pins and contacts 1070. The circuitry 1010 of channel 1005 (A) may beswitched into a current driver mode or configuration 1072, the circuitry1010 of channel 1005 (B) may be switched into a feedback mode and/or aground mode or configuration 1073, and the circuitry 1010 of channel1005 (C) may be switched into a current measurement mode orconfiguration 1074. In some embodiments, the circuitry 1010 of channel1005 (A) comprises a first amplifier 1075 connected to one or morecontacts of the one or more light emitters 1060, the circuitry 1010 ofchannel 1005 (B) comprises one or more feedback resistors 1077 connectedto one or more contacts of the one or more light emitters 1060 and/or aground 1078 connected to one or more contacts of the one or more lightemitters 1060 and/or one or more light detectors 1067, and the circuitry1010 of channel 1005 (C) comprises a second amplifier 1080 connected toone or more contacts of the one or more light detectors 1067. Thecurrent driver measurement mode or configuration 1072, the feedback modeand/or a ground mode or configuration 1073, and the current measurementmode or configuration 1074, can be enabled or disabled from channels1005 (A), (B), and (C) at any time after power-up such as upon insertionand identification of a type of testing device inserted into theanalyzer, or relocated to other channels as necessary.

In accordance with yet other aspects of the present invention, theuniversal channel circuitry is configured to provide multiple electrodeor sensor capability (e.g., optical, electrochemical, and conductometricsensors, as described with reference to FIGS. 8A and 8B). For example,any channel (A) may be assigned to one or more light emitters of atesting device via a first pair of pins and contacts and a second pairof pins and contacts, any other channel 1005 (B) may be assigned to theto one or more light emitters and/or one or more light detectors of thetesting device via a second pair of pins and contacts, and any otherchannel (C) may be assigned to one or more light detectors of thetesting device via a third pair of pins and contacts, as similarlydescribed with reference to FIG. 10G. Additionally, any other channel(D) may be assigned to a counter electrode of the testing device via afourth pair of pins and contacts, any other channel (E) may be assignedto a reference electrode of the testing device via fifth pair of pinsand contacts, and channel (C) (optionally any other channel (F)) may beassigned to a working electrode of the testing device via the third pairof pins and contacts (optionally another pair of pins and contacts), assimilarly described with reference to FIG. 10F. Moreover, any channel(G) may be assigned to a conductometric low electrode of the testingdevice via the second pair of pins and contacts (optionally another pairof pins and contacts) and any other channel (H) may be assigned to aconductometric high electrode of a testing device via a sixth pair ofpins and contacts, as similarly described with reference to FIG. 10E.

The circuitry of channel (A) may be switched into a current driver modeor configuration, the circuitry of channel (B) may be switched into afeedback mode and/or a ground mode or configuration, the circuitry ofchannel (C)/(F) may be switched into a current measurement mode orconfiguration, the circuitry of channel (D) may be switched into countermeasurement mode or configuration, the circuitry of channel (E) may beswitched into reference measurement mode or configuration, the circuitryof channel (G) may be switched into a low conductometric measurementmode or configuration, and the circuitry of channel (H) may be switchedinto a high conductometric measurement mode or configuration. Thevarious measurement modes or configurations can be enabled or disabledfrom the various channels at any time after power-up such as uponinsertion and identification of a type of testing device inserted intothe analyzer, or relocated to other channels as necessary.

While the universal channel circuitry has been described at some lengthand with some particularity with respect to a specific design and/orperformance need, it is not intended that the universal channelcircuitry be limited to any such particular design and/or performanceneed. Instead, it should be understood the universal channel circuitryconfigurations described herein are exemplary embodiments, and that theuniversal channel circuitry configurations are to be construed with thebroadest sense to include variations of the specific design and/orperformance need described herein, as well as other variations that arenot described with particularity herein. In particular, the channels,the modes or configurations, the pairs of pins and contacts, theelectrodes, and the sensors discussed in the various systems and devicesmay be combined, connected, adjusted or modified to meet specific designand/or performance needs. Furthermore, it is to be understood that otherstructures illustrated in the figures may have been omitted from thedescription of the universal channel circuitry for clarity. The omittedstructures may include, for example, logic gates, resistors, amplifiers,etc., and such omitted structures and their layout in the circuitdiagrams are incorporated herein in their entireties for all purposes.

Combined Immunoassay Methods

FIGS. 11-16 show exemplary flowcharts for performing the process stepsof the present invention. The steps of FIGS. 11-16 may be implementedusing the computing devices and systems described above with respect toFIGS. 1-10G. Specifically, the flowcharts in FIGS. 11-16 illustrate thearchitecture, functionality, and operation of possible implementationsof the systems, methods and computer program products according toseveral embodiments of the present invention. In this regard, each blockin the flowcharts may represent a module, segment, or portion of code,which comprises one or more executable instructions stored onnon-transitory machine readable storage medium that when executed by oneor more processors (e.g., a processor of the analyzer) cause the one ormore processors to perform the specified logical function(s) within theone or more executable instructions. It should also be noted that, insome alternative implementations, the functions noted in the blocks mayoccur out of the order noted in the figure. For example, two blocksshown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the flowchart illustrations, and combinations ofblocks in the flowchart illustrations, can be implemented by specialpurpose hardware-based systems that perform the specified functions oracts, or combinations of special purpose hardware and computerinstructions.

FIG. 11 illustrates a method 1100 (with reference to the testing device400 as illustrated in FIGS. 4A-4J) of using a testing device to performan optical assay in accordance with one embodiment of the invention. Atstep 1105, an unmetered biological sample may be introduced into asample chamber (e.g., the sample holding chamber 410 described withrespect to FIGS. 4G and 4H) of a testing device, through a sample entryport (e.g., sealable sample entry port 406 described with respect toFIGS. 4B and 4C). Optionally at step 1110, the biological sample may befiltered to remove cells such that only a plasma fraction of the samplereaches the sensors (e.g., if the cells are not substantially removedthey may scatter the light from the LED and affect assay performance).In some embodiments, the sample holding chamber comprises the filtermaterial such that only the plasma fraction reaches the sample meteringportion of the device. In other embodiments, a first conduit (e.g.,conduit 431 described with respect to FIG. 4A) comprises the filtermaterial such that the metered portion of the sample is filtered toremove the cells. At step 1115, a capillary stop (e.g., capillary stop412 described with respect to FIGS. 4G and 4H) may prevent passage ofthe sample into the first conduit (e.g., conduit 431 described withrespect to FIG. 4A) at this stage, and the sample chamber is filled withthe sample. The capillary stop at the end of the sample chamber delimitsa metered portion of the biological sample. At step 1120, a lid (e.g.,closable sealing member 408 described with respect to FIGS. 4A and 4B)maybe closed to prevent leakage of the biological sample from thesensing device. While the biological sample is within sample chamber orthe first conduit, the biological sample may be optionally amended atstep 1125 with a compound or compounds (e.g., reagents such as enzymes,enzyme substrate, activators, stabilizers, buffers, enzyme-labeledantibody conjugate and the like) present initially as a dry coating onthe inner surface of the sample chamber or first conduit.

At step 1130, the sensing device may be inserted into an analyzer (e.g.,analyzer 105 described with respect to FIG. 1) in accordance with someaspects of the present invention. Optionally at step 1135, insertion ofthe sensing device into the analyzer may activate a first pump (e.g.,the portion of the flexible zone 436 as described with respect to FIGS.4A and 4B) or mechanism that punctures a fluid-containing package whenthe package is pressed against a spike (e.g., spike 425 as describedwith respect to FIGS. 4G and 4H). Fluid (e.g., a substrate) may therebybe expelled into a second conduit (e.g., conduit 422 as described withrespect to FIGS. 4G and 4H) that is in fluidic communication with thefirst conduit. A constriction in the second conduit prevents furthermovement of the fluid. At step 1040, operation of a second pump (e.g.,displaceable membrane 426 as described with respect to FIGS. 4A, 4B, 4G,and 4H) by the analyzer applies pressure to an air-bladder of thesensing device, forcing air through a third conduit (e.g., conduit 429as described with respect to FIGS. 4G and 4H) and into the samplechamber at a predetermined location.

At step 1145, the metered portion of the biological sample is expelledthrough the capillary stop by air pressure produced within theair-bladder at step 1140 into the first conduit. Optionally at step1150, the biological sample is moved forward within the first conduit toa portion of the first conduit (e.g., conduit 431 as described withrespect to FIG. 4A) that is exposed to a sensor chip (e.g., sensor chip600 as described with respect to FIG. 6A) by air pressure producedwithin the air-bladder such that the biological specimen can be amendedwith a compound or compounds (e.g., reagents such as enzymes, enzymesubstrate, activators, stabilizers, buffers, enzyme-labeled antibodyconjugate and the like) present initially as a dry coating on a portionof the sensor chip (i.e., one or more reagent regions). Additionally oralternatively, the fluid in the second conduit may be moved past theconstriction into the first conduit and into contact with the biologicalspecimen by air pressure produced by the first pump. The fluid mayinclude a substrate that may be acted upon by the biological specimenand/or amended compounds to produce a chromatic substance. To facilitatethe dissolution of the substrate, compound or compounds in thebiological sample and/or promote efficient reaction, the biologicalsample may be oscillated by air pressure produced within theair-bladder. In one embodiment, an oscillation frequency of betweenabout 0.2 Hz and about 5 Hz is used, most preferably about 0.7 Hz.

At step 1155, the biological sample is move forward within the firstconduit to a portion of the first conduit (e.g., conduit 431 asdescribed with respect to FIG. 4A) that is exposed to the sensor chip(e.g., sensor chip 600 as described with respect to FIG. 6A) by airpressure produced within the air-bladder such that analysis (e.g.,optical analysis) of the biological specimen can be performed. Invarious embodiments, the biological sample is moved forward within thefirst conduit to a position over an optical sensor such that one or morelight emitters can transmit incident light of one or more wavelengthsinto the portion of the first conduit and the biological specimen. Uponthe incident light striking the biological sample, photons that match anenergy gap of a target analyte or a chromatic substance related to apresence of the target analyte present in the biological specimen areabsorbed. Other photons transmit through the first conduit andbiological specimen unaffected. The one or more light detectors collectthe photons of light transmitted through the first conduit and thebiological sample, and convert the transmitted photons of light intocurrent. At step 1060, the current is transmitted to the analyzer as anoutput signal via a conductive contact, and the analyzer compares theattenuation of the transmitted light with the incident light to obtainan absorption spectrum and converts the output signal to an analytesignal proportional to the light received from the conduit and collectedby the one or more light detectors.

FIG. 12 illustrates a method 1200 (with reference to the testing device400 as illustrated in FIGS. 4A-4J) of using a testing device to performan optical assay and an electrochemical assay in accordance with oneembodiment of the invention. At step 1205, an unmetered biologicalsample may be introduced into a sample chamber (e.g., the sample holdingchamber 410 described with respect to FIGS. 4G and 4H) of a testingdevice, through a sample entry port (e.g., sealable sample entry port406 described with respect to FIGS. 4B and 4C). Optionally at step 1210,the biological sample may be filtered to remove cells such that only aplasma fraction of the sample reaches the sensors (e.g., if the cellsare not substantially removed they may scatter the light from the LEDand affect assay performance). In some embodiments, the sample holdingchamber comprises the filter material such that only the plasma fractionreaches the sample metering portion of the device. In other embodiments,a first conduit (e.g., conduit 431 described with respect to FIG. 4A)comprises the filter material such that the metered portion of thesample is filtered to remove the cells. At step 1215, a capillary stop(e.g., capillary stop 412 described with respect to FIGS. 4G and 4H) mayprevent passage of the sample into the first conduit (e.g., conduit 431described with respect to FIG. 4A) at this stage, and the sample chamberis filled with the sample. The capillary stop at the end of the samplechamber delimits a metered portion of the biological sample. At step1220, a lid (e.g., closable sealing member 408 described with respect toFIGS. 4A and 4B) maybe closed to prevent leakage of the biologicalsample from the sensing device. While the biological sample is withinsample chamber or the first conduit, the biological sample may beoptionally amended at step 1225 with a compound or compounds (e.g.,reagents such as enzymes, enzyme substrate, activators, stabilizers,buffers, enzyme-labeled antibody conjugate and the like) presentinitially as a dry coating on the inner surface of the sample chamber orfirst conduit.

At step 1230, the sensing device may be inserted into an analyzer (e.g.,analyzer 105 described with respect to FIG. 1) in accordance with someaspects of the present invention. At step 1235, insertion of the sensingdevice into the analyzer may activate a first pump (e.g., the portion ofthe flexible zone 436 as described with respect to FIGS. 4A and 4B) ormechanism that punctures a fluid-containing package when the package ispressed against a spike (e.g., spike 425 as described with respect toFIGS. 4G and 4H). Fluid (e.g., a substrate) may thereby be expelled intoa second conduit (e.g., conduit 422 as described with respect to FIGS.4G and 4H) that is in fluidic communication with the first conduit. Aconstriction in the second conduit prevents further movement of thefluid. At step 1240, operation of a second pump (e.g., displaceablemembrane 426 as described with respect to FIGS. 4A, 4B, 4G, and 4H) bythe analyzer applies pressure to an air-bladder of the sensing device,forcing air through a third conduit (e.g., conduit 429 as described withrespect to FIGS. 4G and 4H) and into the sample chamber at apredetermined location.

At step 1245, the metered portion of the biological sample is expelledthrough the capillary stop by air pressure produced within theair-bladder at step 1240 into the first conduit. Optionally at step1250, the biological sample is moved forward within the first conduit toa portion of the first conduit (e.g., conduit 431 as described withrespect to FIG. 4A) that is exposed to a sensor chip (e.g., sensor chip600 as described with respect to FIG. 6A) by air pressure producedwithin the air-bladder such that the biological specimen can be amendedwith a compound or compounds (e.g., (e.g., reagents such as enzymes,enzyme substrate, activators, stabilizers, buffers, enzyme-labeledantibody conjugate and the like) present initially as a dry coating on aportion of the sensor chip (i.e., one or more reagent regions).Additionally or alternatively, the fluid in the second conduit may bemoved past the constriction into the first conduit and into contact withthe biological specimen by air pressure produced by the first pump. Thefluid may include a substrate that may be acted upon by the biologicalspecimen and/or amended compounds to produce a chromatic substance. Tofacilitate the dissolution of the substrate, compound or compounds inthe biological sample and/or promote efficient reaction, the biologicalsample may be oscillated by air pressure produced within theair-bladder. In one embodiment, an oscillation frequency of betweenabout 0.2 Hz and about 5 Hz is used, most preferably about 0.7 Hz.

At step 1255, the biological sample is moved forward within the firstconduit to a position over a first sensor (e.g., an optical sensor) byair pressure produced within the air-bladder. In various embodiments,the biological sample is moved forward within the first conduit to aposition over an optical sensor such that one or more light emitters cantransmit incident light of one or more wavelengths into the portion ofthe first conduit and the biological specimen. Upon the incident lightstriking the biological sample, photons that match an energy gap of atarget analyte or a chromatic substance related to a presence of thetarget analyte present in the biological specimen are absorbed. Otherphotons transmit through the first conduit and biological specimenunaffected. The one or more light detectors collect the photons of lighttransmitted through the first conduit and the biological sample, andconvert the transmitted photons of light into current. At step 1260, thecurrent is transmitted to the analyzer as an output signal via aconductive contact, and the analyzer compares the attenuation of thetransmitted light with the incident light to obtain an absorptionspectrum and converts the output signal to an analyte signalproportional to the light received from the conduit and collected by theone or more light detectors.

Optionally at step 1265, the biological sample is moved forward suchthat the biological specimen can be amended with a compound or compounds(e.g., reagents such as an enzyme and enzyme substrate-labeled antibodyconjugate) present initially as a dry coating on a portion of the sensorchip (i.e., one or more reagent regions). To facilitate the dissolutionof the compound or compounds in the biological sample and/or promoteefficient reaction, the biological sample may be oscillated over the oneor more reagent regions by air pressure produced within the air-bladder.In one embodiment, an oscillation frequency of between about 0.2 Hz andabout 5 Hz is used, most preferably about 0.7 Hz. At step 1270, thebiological sample is moved forward within the first conduit to aposition over a second sensor (e.g., an amperometric sensor) by airpressure produced within the air-bladder. Optionally at step 1275, topromote efficient reaction product formation sandwich formation on ornear the surface of the second sensor comprising a biolayer, thebiological sample may be oscillated over the second sensors by airpressure produced within the air-bladder. In one embodiment, anoscillation frequency of between about 0.2 Hz and about 5 Hz is used,most preferably about 0.7 Hz

At step 1280, the biological sample is displaced from the first conduitby further pressure applied to air-bladder, and the biological samplepasses to a waste chamber (e.g., waste chamber 416 as described withrespect to FIGS. 4A and 4G.). At optional step 1285, one or more airsegments (meniscus) may be produced within the first conduit by anysuitable means, including a passive means, an embodiment of which isdescribed in detail in U.S. Pat. No. 7,682,833, which is incorporatedherein by reference in its entirety, or an active means including atransient lowering of the pressure within the first conduit using thesecond pump whereby air is drawn into the first conduit through a flapor valve. The one or more air segments are extremely effective atclearing or rinsing the biological sample-contaminated fluid from thefirst conduit. For example, a leading and/or trailing edge of the one ormore air segments may be passed a number of times over the first andsecond sensors to rinse and resuspend extraneous material that may havebeen deposited from the biological sample. Extraneous material includesany material other than specifically bound analyte oranalyte/antibody-enzyme conjugate complex. However, in accordance withvarious embodiments, the clearing or rinsing step 1285 using the one ormore air segments is not sufficiently protracted or vigorous so as topromote substantial dissociation of specifically bound analyte oranalyte/antibody-enzyme conjugate complex from a biolayer.

Optionally at step 1290, the fluid in the second conduit is moved pastthe constriction into the first conduit and into contact with the secondsensor by air pressure produced by the first pump. The fluid may includean optical calibrator, e.g. a known concentration of a dye with a knownextinction coefficient, substrate or signal agent and the enzymeremaining within the first conduit and immobilized on or near the secondsensor either produces an electroactive species from an electro-inactivesubstrate or destroys an electroactive substrate. In some embodiments,the fluid may be applied to the second sensor to wash the biologicalsample from the second sensor. At step 1295, a change in current orpotential generated by the production or destruction of theelectroactive species at the second sensor and the change is transmittedas a function of time to the analyzer via a conductive contact, and theanalyzer performs analysis of the change in current or potential toidentify the presence and/or concentration of the target analyte in thebiological specimen.

As should be understood, the previous steps could be split up into twoor more processes for using two or more testing devices to perform anoptical assay and an electrochemical assay in accordance withalternative embodiments of the invention. For example, the stepspertaining to the optical assay could be performed via an opticaltesting device and subsequently the steps pertaining to theelectrochemical assay could be performed via an electrochemical testingdevice, or vice versa.

FIG. 13 illustrates a method 1300 of performing an optical assay fordetermining the presence and/or concentration of an analyte in abiological sample (e.g., whole blood) in accordance with variousembodiments of the invention. At step 1305, an operating state signal isreceived that is indicative of a type of test cartridge inserted into ananalyzer. In some embodiments, the operating state signal comprises avalue of a measured resistance between contacts of the test cartridgeand a shorting bar. For example, in order to impart cartridgeidentification functionality into a test cartridge, an additionalmechanism or means may be included in the sensor chip arrangement forcartridge identification. In certain embodiments, a resistor can beimplemented between contacts. The resistance of the resistor may bemeasured by a detector (e.g., processor) by applying a small voltage,e.g., 1 mV, between the contacts, subsequent to (e.g., immediatelyafter) the cartridge being inserted into the analyzer. The value of themeasured resistance can then be used for cartridge identification. Forexample, each cartridge type (e.g., i-STAT® cartridges EC8+, CG8+, EG7+,CHEM8+, etc.) may be associated with a certain resistance or resistancerange such that a measured resistance of the cartridge may be used toidentify the type of cartridge using a look-up table.

In alternative embodiments, the operating state signal comprises a valueobtained from a barcode located on the test cartridge or a package ofthe test cartridge. For example, an imaging area of the test cartridgemay be used to scan a barcode to obtain a value using the barcode reader135 of the instrument 110, as described with respect to FIG. 1. Thevalue of barcode can then be used for cartridge identification. Forexample, each cartridge type (e.g., i-STAT® cartridges EC8+, CG8+, EG7+,CHEM8+, etc.) may be associated with a certain value such that a scannedvalue of the cartridge may be used to identify the type of cartridgeusing a look-up table retained in the instrument.

At step 1310, information regarding sensors of the test cartridge aredetermined based on the identified type of cartridge. In certainembodiments, determining the information comprises: identifying, basedon a value of the operating state signal, the type of test cartridgeusing a look-up table, and obtaining, based on the type of testcartridge, the information regarding the sensors from a database, wherethe database has information for each type of test cartridge. In variousembodiments, the information indicates the type of sensors of the testcartridge (e.g., one or more optical sensors, one or more referenceelectrode, one or more electrochemical sensors, etc) and the position ofconductive contacts connected to the sensors of the test cartridge Inaddition or alternative to obtaining information regarding the type ofsensors and the position of conductive contacts from the database viathe identified type of testing cartridge, the type of sensors andposition of the conductive contacts may be identified using informationobtained regarding the connector pins in contact with the variousconductive contacts of the testing cartridge. For example, the analyzerconnector may be a linear array of connector pins, e.g., pins one totwenty. The type of sensors and position of the conductive contacts maybe identified via the position of each pin relative to the contacts. Forexample, a light emitter of an optical sensor may be connected via acontact to a pin “x” (e.g., pin 11) and a light detector of the opticalsensor may be connected via another contact to a pin “y” (e.g., 12), andthus since both pins 11 and 12 are being used, the type of sensor(optical) and components (e.g., light emitter and light detector)connected to the contacts can be identified via the database.Consequently, as described herein, the analyzer may then assign channelsof the universal circuitry to the appropriate pins for the types ofsensors determined to be in the identified testing cartridge. As shouldbe understood, once a test cycle is run and the testing cartridge isremoved from the instrument or analyzer, the channels of the universalcircuitry can be reassigned to the same or different connector pins whena new testing cartridge is inserted into the analyzer.

At step 1315, a first channel is assigned to the light emitter via: (i)the first contact and a corresponding first pin, and optionally, (ii)the second contact and a corresponding second pin. At step 1320, asecond channel is assigned to the light detector via the third contactand a corresponding third pin.

At step 1325, the circuitry of the first channel is switched to acurrent driver mode. In some embodiments, the switching the circuitry ofthe first channel comprises modifying switching elements of thecircuitry such that the first channel is configured to apply the drivecurrent via the first contact and the corresponding first pin to thelight emitter. At step 1330, the circuitry of the second channel isswitched to a current measurement mode. In some embodiments, theswitching the circuitry of the second channel comprises modifyingswitching elements of the circuitry such that the second channel isconfigured to convert output current received from the light detector toa measurable voltage proportional to an amount light detected by thelight detector.

At step 1335, a drive current is applied to the light emitter using thefirst channel. The applying the drive current to the light emittercauses the light emitter to generate output current and light comprisinga predetermined wavelength that is projected into a portion of aconduit. Optionally at step 1340, the output current generated by thelight emitter is received at the first channel from the second contactand the corresponding second pin, and the output current is applied to afeedback resistor to establish a constant current for the drive current.

At step 1345, the light detector converts the photons of light receivedfrom the light emitter to an output current and sends the output currentto the third contact as an output signal. At step 1350, the outputsignal from the light detector is received at the second channel via thethird contact and the corresponding third pin. The output signal may beconverted, using the second channel, to a measurable voltage or analytesignal proportional to an amount light received from the portion of theconduit and detected by the light detector. At step 1355, a qualitative,semi-quantitative, or quantitative value that is proportional to anamount of target analyte in the biological specimen is determined basedon the measurable voltage or analyte signal.

FIG. 14 illustrates a method 1400 of performing an optical assay andusing a conductometric sensor to determine a location of a biologicalsample in a test cartridge and/or determine a hematocrit level of thebiological specimen. At step 1405, a qualitative, semi-quantitative, orquantitative value is determined based on a measurable voltage that isproportional to an amount of target analyte in the biological specimenin accordance with steps 1305-1355 of method 1300. At step 1410,additional/alternative information regarding sensors of the testcartridge is determined based on the type of the test cartridge and/orthe pins being used. In various embodiments, the information indicatesthat one of the first contact, the second contact, the third contact, ora fourth contact is connected to a first conductometric electrode, andone of the first contact, the second contact, the third contact, or thefourth contact is connected to a second conductometric electrode.

At step 1415, a third channel is assigned to the first conductometricelectrode via the first contact, the second contact, the third contact,or a fourth contact and the corresponding first pin, the second pin, thethird pin, or a fourth pin. At step 1420, a fourth channel is assignedto the second conductometric electrode via the first contact, the secondcontact, the third contact, or a fourth contact and the correspondingfirst pin, the second pin, the third pin, or a fourth pin. At step 1425,the circuitry of the third channel is switched to a high conductometricmode. In some embodiments, the switching the circuitry of the thirdchannel comprises modifying switching elements of the circuitry suchthat the third channel is configured to apply a potential to the firstconductometric electrode and measure a voltage change across thebiological specimen that is proportional to conductivity of thebiological specimen. At step 1430, the circuitry of the fourth channelis switched to a low conductometric mode. In some embodiments, theswitching the circuitry of the fourth channel comprises modifyingswitching elements of the circuitry such that the fourth channel isconfigured to apply a potential to the second conductometric electrodeand measure a voltage change across the biological specimen that isproportional to conductivity of the biological specimen.

At step 1435, a potential is applied to the to the first conductometricelectrode using the third channel. At step 1440, a voltage change acrossthe biological specimen is measured, using, using the third channel andthe fourth channel, that is proportional to conductivity of thebiological specimen. At step 1445, a position of the biological specimenis determined within the testing device based on the voltage changeacross the biological specimen. Optionally at step 1450, a hematocritlevel of the biological specimen is determined by comparing the voltagechange to known values of hematocrit on a calibration curve andconverting the value of the hematocrit to a rating for the hematocritlevel.

FIG. 15 illustrates a method 1500 of performing an optical assay andelectrochemical assay using a same testing device. At step 1505, aqualitative, semi-quantitative, or quantitative value is determinedbased on a measurable voltage that is proportional to an amount oftarget analyte in the biological specimen in accordance with steps1305-1355 of method 1300. At step 1510, additional/alternativeinformation regarding sensors of the test cartridge is determined basedon the type of the test cartridge and/or the pins being used. In variousembodiments, the information indicates that a fourth contact isconnected to a counter electrode, a fifth contact is connected to areference electrode, and the third contact or a sixth contact isconnected to a working electrode (e.g., an amperometric electrode).

At step 1515, a third channel is assigned to the counter electrode viathe fourth contact and a corresponding fourth pin. At step 1520, afourth channel is assigned to the reference electrode via the fifthcontact and a corresponding fifth pin. At step 1525, the second channelis assigned to the working electrode via the third contact and thecorresponding third pin or the sixth contact and a corresponding sixthpin. At step 1530, the circuitry of the third channel is switched to acounter measurement mode. In some embodiments, the switching thecircuitry of the third channel comprises modifying switching elements ofthe circuitry such that the third channel is configured to apply apotential that is optionally not measured and is adjusted so as tobalance the reaction occurring at the working electrode. Thisconfiguration allows the potential of the working electrode to bemeasured against a known electrode (i.e., the counter electrode) withoutcompromising the stability of the reference electrode by passing currentover the reference electrode. At step 1535, the circuitry of the fourthchannel is switched to a reference measurement mode. In someembodiments, the switching the circuitry of the fourth channel comprisesmodifying switching elements of the circuitry such that the fourthchannel is configured to apply a stable potential to the referenceelectrode, which may be used as a reference for measurements made by theworking electrode.

At step 1540, a potential is applied to the counter electrode using thethird channel. At step 1545, a potential is applied to the referenceelectrode using the fourth channel. At step 1550, a potential is appliedto the working electrode using the second channel. At step 1555, acurrent change across the biological specimen is measured, using thesecond channel, that is proportional to a concentration of anothertarget analyte within the biological specimen. In various embodiments,the counter electrode and the reference electrode are used inconjunction with the working electrode to measure the current changeacross the biological specimen. At step 1560, the concentration ofanother target analyte within the biological specimen is determinedbased on the current change across the biological specimen.

FIG. 16 illustrates a method 1600 of performing an optical assay andelectrochemical assay using different testing devices. At step 1605, afirst test device (e.g., an optical testing device) is received and aqualitative, semi-quantitative, or quantitative value is determinedbased on a measurable voltage that is proportional to an amount oftarget analyte in the biological specimen in accordance with steps1305-1355 of method 1300. At step 1610 (subsequent to step 1605), asecond test device (e.g., an electrochemical testing device) is insertedinto the analyzer and another operating state signal is received that isindicative of a type of test cartridge inserted into the analyzer. Insome embodiments, the operating state signal comprises a value of ameasured resistance between contacts of the test cartridge and ashorting bar, as described with respect to FIG. 13. In alternativeembodiments, the operating state signal comprises a value obtained froma barcode located on the test cartridge or a package of the testcartridge, as described with respect to FIG. 13.

At step 1615, information regarding sensors of the test cartridge aredetermined based on the identified type of cartridge, as described withrespect to FIG. 13. For example, the analyzer connector may be a lineararray of connector pins, e.g., pins one to twenty. The type of sensorsand position of the conductive contacts may be identified via theposition of each pin relative to the contacts. For example, anamperometric electrode may be connected via a contact to a pin “x”(e.g., pin 5) and reference electrode may be connected via anothercontact to a pin “y” (e.g., 6), and thus since both pins 5 and 6 arebeing used, the type of sensor (amperometric) and components (e.g.,amperometric electrode and reference electrode) connected to thecontacts can be identified via the database. Consequently, as describedherein, the analyzer may then assign channels of the universal circuitryto the appropriate pins for the types of sensors determined to be in theidentified testing cartridge. As should be understood, once a test cycleis run and the testing cartridge is removed from the instrument oranalyzer, the channels of the universal circuitry can be reassigned tothe same or different connector pins when a new testing cartridge isinserted into the analyzer.

At step 1620, a first channel is assigned to a working electrode via afirst contact and a corresponding first pin. At step 1625, a secondchannel is assigned to a counter electrode via a second contact and acorresponding second pin. At step 1630, a third channel is assigned tothe reference electrode via the third contact and a corresponding thirdpin. At step 1635, the circuitry of the first channel is switched to ameasurement mode (e.g., an amperometric measurement mode). In someembodiments, the switching the circuitry of the first channel comprisesmodifying switching elements of the circuitry such that the firstchannel is configured to apply a potential via the first contact and thecorresponding first pin to working electrode. At step 1640, thecircuitry of the second channel is switched to a counter measurementmode. In some embodiments, the switching the circuitry of the secondchannel comprises modifying switching elements of the circuitry suchthat the second channel is configured to apply a potential that isoptionally not measured and is adjusted so as to balance the reactionoccurring at the working electrode. This configuration allows thepotential of the working electrode to be measured against a knownelectrode (i.e., the counter electrode) without compromising thestability of the reference electrode by passing current over thereference electrode. At step 1645, the circuitry of the third channel isswitched to a reference measurement mode. In some embodiments, theswitching the circuitry of the third channel comprises modifyingswitching elements of the circuitry such that the third channel isconfigured to apply a stable potential to the reference electrode, whichmay be used as a reference for measurements made by the workingelectrode.

At step 1650, a potential is applied to the counter electrode using thesecond channel. At step 1655, a potential is applied to the referenceelectrode using the third channel. At step 1660, a potential is appliedto the working electrode using the first channel. At step 1665, acurrent change across the biological specimen is measured, using thefirst channel, that is proportional to a concentration of another targetanalyte within the biological specimen. In various embodiments, thecounter electrode and the reference electrode are used in conjunctionwith the working electrode to measure the current change across thebiological specimen. At step 1670, the concentration of another targetanalyte within the biological specimen is determined based on thecurrent change across the biological specimen.

As should be understood, the first test device and the second testdevice could be received in reverse order with an electrochemicaltesting device received first and an optical testing device receivedsecond. Moreover, it should be understood that more than two cartridgescould be received subsequent to one another and the analyzer iscontemplated to perform analytical tests on tens to hundreds of varioustesting cartridges per day.

While the invention has been described in detail, modifications withinthe spirit and scope of the invention will be readily apparent to theskilled artisan. It should be understood that aspects of the inventionand portions of various embodiments and various features recited aboveand/or in the appended claims may be combined or interchanged either inwhole or in part. In the foregoing descriptions of the variousembodiments, those embodiments which refer to another embodiment may beappropriately combined with other embodiments as will be appreciated bythe skilled artisan. Furthermore, the skilled artisan will appreciatethat the foregoing description is by way of example only, and is notintended to limit the invention.

We claim:
 1. A system for performing multiple assays on a biologicalsample, comprising: an analyzer comprising: a cartridge port for matingwith a test cartridge, a multi-terminal connector, a processor, memorycoupled to the processor, and universal channel circuitry, wherein theuniversal channel circuitry comprises a first channel, a second channel,and a third channel; a first test cartridge comprising a light emitterconnected to a first contact and a light detector connected to a secondcontact; and a second test cartridge comprising an amperometricelectrode connected to a third contact and a reference electrodeconnected to a fourth contact, wherein the first contact is electricallyconnectable to a first pin of the multi-terminal connector, and thesecond contact is electrically connectable to a second pin of themulti-terminal connector; wherein the third contact is electricallyconnectable to the first pin of the multi-terminal connector, and thefourth contact is electrically connectable to the second pin of themulti-terminal connector; wherein the first pin is electricallyconnectable to the first channel, and the second pin is electricallyconnectable to the second channel; wherein when the first test cartridgeis inserted into the port of the analyzer, the first channel comprisescircuitry including switches that are arranged such that the firstchannel is configured in a current driver mode, and the second channelcomprises circuitry including switches that are arranged such that thesecond channel is configured in a current measurement mode; and whereinwhen the second test cartridge is inserted into the port of theanalyzer, the first channel is configured in an amperometric measurementmode, and the second channel is configured in a reference measurementmode.
 2. The system of claim 1, wherein the processor is configured todetermine a qualitative, semi-quantitative, or quantitative valueproportional to an amount of a target analyte in the biological samplebased on the analyte signal.
 3. The system of claim 2, wherein thetarget analyte is selected from the group consisting of: human chorionicgonadotropin, glucose, lactate, creatinine, urea, prothrombin time (PT),activated partial thromboblastin time (APTT), activated clotting time(ACT), D-dimer, prostate-specific antigen (PSA), creatine kinase-MB(CKMB), brain natriuretic peptide (BNP), troponin I (TnI), cardiactroponin (cTnI), human chorionic gonadotrophin, troponin T, troponin C,myoglobin, neutrophil gelatinase-associated lipocalin (NGAL),galectin-3, prostate-specific antigen (PSA), parathyroid hormone (PTH),galectin-3, aspartate aminotransferase (AST), alanine aminotransferase(ALT), albumin, total protein, bilirubin, and alkaline phosphatase(ALP).
 4. The system of claim 1, wherein the first test cartridgefurther comprises a mirrored reflector that reflects light from thelight emitter through the conduit to the light detector.
 5. The systemof claim 4, wherein the mirrored reflector is at least a portion of asurface of the conduit.
 6. The system of claim 1, wherein the first testcartridge further comprises a filter between the sample receivingchamber and the conduit, and the filter is configured to retain bloodcells from the biological sample and permit passage of plasma.
 7. Thesystem of claim 1, wherein the cartridge port is configured to thereceive the first test cartridge and the second test cartridgesequentially.
 8. A system comprising: one or more processors; and memorycoupled to the one or more processors, the memory encoded with a set ofinstructions configured to perform a process comprising: receiving anoperating state signal from a first test cartridge indicative of a firsttype of cartridge inserted into an analyzer; determining that the firsttype of cartridge is the first test cartridge having a first contactconnected to a light emitter and a second contact connected to a lightdetector; assigning a first channel to the light emitter via the firstcontact and a corresponding first pin; assigning a second channel to thelight detector via the second contact and a corresponding second pin;switching circuitry of the first channel to a current driver mode;switching circuitry of the second channel to a current measurement mode;performing an optical analytical test using the first channel and thesecond channel; receiving an operating state signal from a second testcartridge indicative of a second type of cartridge inserted into theanalyzer; determining that the second type of cartridge is the secondtest cartridge having a first contact connected to an amperometricelectrode and a second contact connected to a reference electrode;assigning a first channel to the amperometric electrode via the firstcontact and another corresponding first pin; assigning a second channelto the reference electrode via the second contact and anothercorresponding second pin; switching circuitry of the first channel to anamperometric measurement mode; switching circuitry of the second channelto a reference measurement mode; and performing an electrochemicalanalytical test using the first channel and the second channel.
 9. Thesystem of claim 8, wherein the receiving the operating state signalindicative of the first type of cartridge and the receiving theoperating state signal indicative of the second type of cartridge arereceived sequentially.
 10. The system of claim 8, wherein the first testcartridge is inserted into the analyzer prior to the second testcartridge being inserted into the analyzer.
 11. The system of claim 8,wherein the second test cartridge is inserted into the analyzer prior tothe first test cartridge being inserted into the analyzer.
 12. Thesystem of claim 8, wherein the performing the optical analytical testcomprises: applying, using the first channel, a drive current to thelight emitter; converting, using the second channel, an output signalreceived from the light detector to an analyte signal proportional to anamount light detected by the light detector; and determining aqualitative, semi-quantitative, or quantitative value proportional to anamount of target analyte in a biological sample in the test cartridgebased on the analyte signal.
 13. The system of claim 12, wherein thetarget analyte is selected from the group consisting of: human chorionicgonadotropin, glucose, lactate, creatinine, urea, prothrombin time (PT),activated partial thromboblastin time (APTT), activated clotting time(ACT), D-dimer, prostate-specific antigen (PSA), creatine kinase-MB(CKMB), brain natriuretic peptide (BNP), troponin I (TnI), cardiactroponin (cTnI), human chorionic gonadotrophin, troponin T, troponin C,myoglobin, neutrophil gelatinase-associated lipocalin (NGAL),galectin-3, prostate-specific antigen (PSA), parathyroid hormone (PTH),galectin-3, aspartate aminotransferase (AST), alanine aminotransferase(ALT), albumin, total protein, bilirubin, and alkaline phosphatase(ALP).
 14. The system of claim 8, wherein the first test cartridgefurther comprises a mirrored reflector that reflects light from thelight emitter through the conduit to the light detector.
 15. The systemof claim 14, wherein the mirrored reflector is at least a portion of asurface of the conduit.
 16. The system of claim 8, wherein the firsttest cartridge further comprises a filter between the sample receivingchamber and the conduit, and the filter is configured to retain bloodcells from the biological sample and permit passage of plasma.
 17. Thesystem of claim 8, wherein the performing the electrochemical analyticaltest comprises: applying, using the second channel, a potential to theamperometric electrode with respect to the reference electrode;measuring, using the first channel, a current change across a biologicalspecimen that is proportional to a concentration of another targetanalyte within the biological specimen; and determining theconcentration of the another target analyte within the biologicalspecimen based on the current change across the biological specimen. 18.The system of claim 8, wherein the operating state signal comprises avalue of a measured resistance between contacts of the first testcartridge or the second test cartridge and a shorting bar.
 19. Thesystem of claim 8, wherein the operating state signal comprises a valueobtained from a barcode located on the first test cartridge or thesecond test cartridge.
 20. The system of claim 8, wherein thedetermining that the first test cartridge has the first contactconnected to the light emitter and the second contact connected to thelight detector, comprises: identifying, based on a value of theoperating state signal, the first type of cartridge using a look-uptable, and obtaining, based on the first type cartridge, informationregarding sensors of the first test cartridge from a database, whereinthe information indicates that the first test cartridge includes anoptical sensor that has the light emitter connected to the first contactand the light detector connected to the second contact.
 21. A system forperforming multiple assays on a biological sample, comprising: ananalyzer comprising: a port, a multi-terminal connector, a processor,and universal channel circuitry, wherein the universal channel circuitrycomprises a first channel, a second channel, and a third channel; and atest cartridge comprising a emitter connected to a first contact, alight detector connected to a second contact, and an amperometricelectrode connected to a third contact, wherein the first contact iselectrically connectable to a first pin of the multi-terminal connector,the second contact is electrically connectable to a second pin of themulti-terminal connector, and the third contact is electricallyconnectable to a third pin of the multi-terminal connector; wherein thefirst pin is electrically connectable to the first channel, the secondpin is electrically connectable to the second channel, and the third pinis electrically connectable to the third channel; and wherein the firstchannel comprises circuitry including switches that are arranged suchthat the first channel is configured in a current driver mode, thesecond channel comprises circuitry including switches that are arrangedsuch that the second channel is configured in a current measurementmode, and the third channel comprises circuitry including switches thatare arranged such that the third channel is configured in anamperometric measurement mode.